Love Triangle: How Trigonometry Shapes the World

by Matt Parker

An ode to triangles, the shape that makes our lives possible   Trigonometry is perhaps the most essential concept humans have ever devised. The simple yet versatile triangle allows us to record music, map the world, launch rockets into space, and be slightly less bad at pool. Triangles underpin our day-to-day lives and civilization as we know it.   In Love Triangle, Matt Parker argues we should all show a lot more love for triangles, along with all the useful trigonometry and geometry they enable. To prove his point, he uses triangles to create his own digital avatar, survive a harrowing motorcycle ride, cut a sandwich, fall in love, measure tall buildings in a few awkward bounds, and make some unusual art. Along the way, he tells extraordinary and entertaining stories of the mathematicians, engineers, and philosophers—starting with Pythagoras—who dared to take triangles seriously.   This is the guide you should have had in high school—a lively and definitive answer to “Why do I need to learn about trigonometry?” Parker reveals triangles as the hidden pattern beneath the surface of the contemporary world. Like love, triangles actually are all around. And in the air. And they’re all you need.

Genres: Nonfiction, Science, Mathematics, Audiobook, Humor, Stem, Comedy

345 pages, Kindle Edition

First published August 20, 2024

About the author

Matt Parker is a former maths teacher who communicates about mathematics via YouTube videos, stand-up comedy, and books.

Librarian note:
There is more than one author in the GoodReads database with this name

Reviews

[aPriL does feral sometimes · Rating 4 out of 5]

Once again I have attempted to read a science book that really is over my paygrade mathematically. But this time, it isn’t because I cannot even begin to be able to understand any of the usually esoteric math that is described or mentioned in passing on those science subjects which rely heavily on maths. This time it’s because much of my memories of math I studied in college has rusted over with decaying proteins, or worse, the brain cells I used to pass my math exams have utterly died. I am in my seventh decade of life, and college was nearly half of a century ago in my past. There was a time when I did very well in Geometry and Algebra and Trigonometry, and even Calculus (shudder). However, it was truly a case of me following instructions without any understanding whatsoever.

Give me a break, people. I have difficulty remembering how to tie my shoes now.

Anyway.

‘Love Triangle’ by Matt Parker is fun to read, and very informative. He includes stories of how triangle area/angles/ratio formulas were discovered, and how they have been used throughout history to build our roads and buildings, and in solving extremely essential and important engineering and physics and art perspective convergence problems, and in history was the key to determining how big the Earth was. I was amazed! And mortified. My knowledge of trigonometry and geometry floated up, slowly, oh my god, so slowly, from the depths where my rusted over memories of past studies reside. I was able to follow most of Matt Parker’s fascinating stories about the practical uses of triangles only generally. And the sine/cosine chapters were very enlightening because of all the maths I took it was those classes where I most of all stared blankly at the work while I solved problems correctly without ANY understanding of it. The last couple of chapters on Fourier transforms and analysis lost me entirely, except that I could grok Fourier maths allowed scientists and musicians to see the different frequencies inside a sound or a molecule. Something like that.

I have copied the book blurb:

”An ode to triangles, the shape that makes our lives possible   Trigonometry is perhaps the most essential concept humans have ever devised. The simple yet versatile triangle allows us to record music, map the world, launch rockets into space, and be slightly less bad at pool. Triangles underpin our day-to-day lives and civilization as we know it.  

In Love Triangle, Matt Parker argues we should all show a lot more love for triangles, along with all the useful trigonometry and geometry they enable. To prove his point, he uses triangles to create his own digital avatar, survive a harrowing motorcycle ride, cut a sandwich, fall in love, measure tall buildings in a few awkward bounds, and make some unusual art. Along the way, he tells extraordinary and entertaining stories of the mathematicians, engineers, and philosophers—starting with Pythagoras—who dared to take triangles seriously.  

This is the guide you should have had in high school—a lively and definitive answer to “Why do I need to learn about trigonometry?” Parker reveals triangles as the hidden pattern beneath the surface of the contemporary world. Like love, triangles actually are all around. And in the air. And they’re all you need.”

The above descriptions about trigonometry are not in the least hyperbolic. Math nerds have made civilization possible, not just space explorations. I don’t know how teachers teach maths today, but in my classes, it was all about memorizing formulas, not about how the formulas were discovered, or how architects, artists, scientists and engineers used them. This book fills in some of THOSE blanks, but unfortunately not the ones in my math education. My innate nerdiness begins and ends with the reading of books and seeing, no, feeling the atoms of meaning in the words. Maths for me are more a memorization exercise in which glimmers of light occasionally break through. I can tell the secrets of physical reality are there, somewhere, in those equations!

The book has lots and lots of pictures, most of which are very necessary. It also has a crazy index section to decipher.

[Jonathan Shaheen · Rating 4 out of 5]

While I loved this book, I wouldn’t recommend it unless you have at least a moderate interest in math. Matt is a funny and easy to understand teacher, but it’s still a math-heavy book. If reading 300 pages about triangles feels a bit daunting, I’d highly recommend his YouTube channel which is more approachable for everyone.

[Sophie · Rating 4 out of 5]

He's done it again! This time with a book about triangles.

Matt Parker's books are always factual, fun and funny, this is no different.

His writing makes you feel you're chatting to a friend rather than reading and learning!

At some points I did feel like I was going through my A-Level physics/maths lessons but that didn't put me off due to the presentation of the examples.

Loved every page and cannot wait for more books by Matt.

Thank you to NetGalley, the publishers and Matt Parker for an eARC of Love Triangle.

[Dana Nourie · Rating 5 out of 5]

I don’t know if I can express how much I appreciate and enjoyed this book. Mathematics is a topic that makes many cringe, and I’m know different. But over the last decade, because of my love of science and wanting to understand the universe, I have been learning. So I’m always looking out for good books on math, books that inspire. And believe me when I say, there are not many of them.

I’ve been struggling with trigonometry for some 3 years, so when I saw this book, the title grabbed me immediately. I’m so glad I bought it. This is not a textbook. It does not tell you how to solve problems, but what it does do is show the beauty of shapes, particularly triangle for how they shape our world. Engineering, science , computing and gaming, and even the natural world relies upon triangles.

The author’s passion comes through as he describes the many ways he uses math, and his love affair with triangles, shapes, and trigonometry. He covers uses from building strong bridges to predicting the orbits of asteroids. He also has a funny and sometimes cheesy sense of humor, corny turns of phrases that make the text all the more endearing.

I will reread this book in the future. It’s one that was hard to put down and will remain on my kitchen table so it’s easy to pick up again. This book is right up there with the Joy of X. I love it that more authors are writing fun books about mathematics and how it’s used everywhere.

[Verity Halliday · Rating 5 out of 5]

Matt Parker is a man who is very excited by triangles and he wants you to be excited by triangles too! The book skips along with humour and enthusiasm which is just so infectious.

I had fun and I learned stuff - what more could you want?

[Steven Robertson · Rating 4 out of 5]

Over all I enjoyed it. Matt Parker is funny and explains topics in a clear and interesting way, knowing how much detail to give so as to not bore the reader.

The topics he chose to speak about were a little applied for my tastes, but I think that issue lies with me.

[Caroline · Rating 3 out of 5]

You can tell how much this guy loves maths and a good triangle. It kept the sections requiring more concentration engaging, especially listening to the audiobook. However, some parts felt like they were geared toward those with a very basic understanding of mathematical principles while others delved deeper without, in my opinion, adequate explanation or lead-in. Still a fun time though and would like to reread it eventually.

[Ashley D · Rating 4 out of 5]

funny! mathy! liked it but not sure it would be up your alley if you don’t like math

[Tyler Critchfield · Rating 4 out of 5]

One of the nerdiest books I've read to date - loved it :)

[Jerry Hillyer · Rating 4 out of 5]

I don't think he's as funny as he thinks. Fun book. Kind of heavy at the last couple of chapters, but I survived. Triangles are fun. I have no use for his disrespect for God or those who believe. It's boring and low hanging fruit. No one ever wants to venture just where all this comes from...it just happened. Boring. But triangles are fun.

[Timothy · Rating 5 out of 5]

I really enjoyed this book! I listened to the audiobook read by the author and that was really fun. I’m already a triangle fan, so I really clicked with this book and enjoyed learning some new things along the way. Great book, would highly recommend!

[Kiwi Lanier · Rating 5 out of 5]

One of my favorite things I've read in a while. He had me once he classified Pythagoras as "the Beyoncé of maths." I'm not even a math person. I just enjoyed learning about this and hearing someone so passionate speak about what they love (listen to this on audio btw)

[Jessica · Rating 4 out of 5]

Some subjects grabbed me more than others. I know the author avoided trig for a good chunk of the beginning of the book but I actually liked trig so I was thrilled when it finally came up. I'm one of those adults who remembers what soh cah toa stands for and that all those triangles come full circle.

I liked the chapter about reducing the number of edges using hexagons. Anytime astronomy concepts came up I was doubly interested and the author talked about how the James Webb Space Telescope was made up of 18 hexagons. Bees make hexagons as well, apparently quite by accident.

The chapter on art was also really good for me. I've been more interested in art lately. I learned about the vanishing point. Also enjoyed the discussion about how our brain's interpretation of what we are seeing can fool us.

Most of the goofy jokes were easy enough for me to get right away, like Hmmmmmmm = Hm^7

The only reason it's not 5 stars is because some of the chapters were really hard for me to get through. Most sports references were lost on me. Also, having a strong background in geometry and trig will definitely help. Some concepts were hard for me to understand. I will hold on to this book in hopes of reading it again!

[Yi · Rating 2 out of 5]

This book does a disservice to Matt.

I enjoy his books and YouTube videos, which is why I'm reading this book.
First of all, what's with the page numbers? I understand that this is a book about math, specifically about triangles, so that angles will appear everywhere throughout the book. But what are the values in the place of page numbers??? Doesn't it warrant an explanation before the page number things? Perhaps in the intro?
I figured it out easily when I got to the value 0.500000 and counted 31. And value 1.000000 is on page 91.
Yes, everything seems to be off by 1, because it starts on 0.000000, so page 0. Where you would normally expect odd page numbers, there are now "even numbers", really the sine of that many degrees.

Page 0.707107 has a picture from a stock photo website. Matt invites readers to find 4 things wrong in the image of a double rainbow. The book is printed in low-resolution black and white. The only one of the 4 things you can see in the picture is about the shape. The other 3 things are about color and which part should be brighter. Needless to say, we are not afforded the opportunity to participate in this exercise.

[Mitchell · Rating 4 out of 5]

As they say, every triangle is a love triangle if you love triangles - which the author clearly does.

It's fascinating how prevalent triangles are in our lives, however much we may not realise it, and how they are so fundamental to so many mathematical concepts. The book is a little light on the deeper mathematics (perhaps worth it to appeal to a larger audience) but it is still well-written and entertaining.

[Christina Dudley · Rating 5 out of 5]

Delightful read on exactly what the title promises. I loved trigonometry in high school, but that was a thousand years ago. So, did I follow all the math in the book? Nope. But I happily skipped over most equations for the stories and the ooh-that's-fascinating moments which filled the book. Funny, too.

I chose this in my eternal struggle to find books my son might like reading, but I beat him to the end of this one.

I will absolutely read more books by this author.

[Dave Godfrey · Rating 4 out of 5]

Always enjoy Matt Parker's books. He blends humor and mathematics into a great story. Most of his chapters discuss items that he covered in his YouTube channel but there was enough new stuff to keep it interesting.

[Richard · Rating 3 out of 5]

Not as good as humble pi

[Casper Vermeeren · Rating 5 out of 5]

Driehoeken zijn alles en alles is driehoeken

[Julian Onions · Rating 4 out of 5]

Fun romp through geometry and trigonometry with more puns than you can shake a stick at. If you follow his YouTube channel quite a lot has been covered there. Still, a fun read.

[Patrick · Rating 3 out of 5]

Listen to as audiobook. Which because of content would be much better as book. So likely would be higher rating of read.

[Helen French · Rating 4 out of 5]

As you should be able to tell from the title - but let me just confirm it - this really is a book all about triangles. Do not buy it if you are not remotely interested in these shapes with three sides! But if you like popular science books, are intrigued by the shapes that make up the universe, don't mind a little mathematics in your reading, or are actually a triangles-big-time-fan, then this book could be for you.

As for me, I like dabbling in a bit of popular science-type reading, but I'm not a mathematician or anywhere near it.

Essentially, the book explores all the ways triangles are used or can be found in the world, with plenty of illustrations and examples to go with it. The writing style is fun and engaging and you can learn a lot! The slight downside to me is that I didn't really find a narrative thread to follow, it was simply interesting a few pages at a time. So I'd read a section and then come back to it later, but there was no desperate urge to read more right away. Saying that, I think that can work well for a non-fiction book. I read it on Kindle, but I think it would be best in physical form where you can leave it somewhere handy and then pick it up for a short read now and then.

Plus, if you know anyone into maths/science/triangles, this would be an awesome gift.

[Ron · Rating 4 out of 5]

This is a book that talks about triangle and trigonometry and where they show up in the world. The author has a sense of humor and it shows up in the book. If you aren't a math person, I'm not sure that you'd appreciate this book as much as a math person.

[Colin Cannon · Rating 3 out of 5]

I love Matt Parker, but the whole book is just recycled stories from his YouTube channel. Maybe there is original stuff at the end, but I wasn’t going to push through. His other books are better (and more mathematically rigorous).

I don’t feel bad about buying the book, because he does good stuff for math educators. I might gift the book to one of my students

[Stacy · Rating 4 out of 5]

In Love Triangle, Matt Parker gives a multitude of examples of triangles used in real life while skimming the surface of the core concepts of triangles, keeping it entertaining with his jokes and stories. The book also includes plenty of illustrations to complement what he is saying.

This was an enjoyable read that you can binge in one sitting or read a few pages at a time, as time allows. I enjoyed that the page numbers at the bottom were the sine of normal page numbers; it was a cute trigonometric quirk! I learned quite a bit about the world while reading this book. I highly suggest checking it out, even if you weren’t a fan of trigonometry or geometry in school!

I received an ARC of this book in return for my unbiased opinion.

[Bunmi · Rating 4 out of 5]

Enjoyed this way more than I'd like to admit. Loved the journey from triangle to geometry to trigonometry and all the way to physics. Prosthaphaeresis was something I thought I had invented. I'm sure it featured at some point in my education in the 90s. According to the book, it was 'a technique used between about 1590 and 1614.' I can confirm I'm not that old.

[Emily Garner · Rating 5 out of 5]

What an absolutely joyous book. I never expected to be so charmed by a book about triangles, but here we are. Matt Parker's writing style is easy to follow, comprehensive and comprehendible, and all-out fun to read.

Here are some of my absolute favourite stand-out facts from this wonderful book. I hope if you choose to read this book, you find more of your own. Trust me - you'll be repeating snippets from this book for weeks!
- "A rainbow is always directly opposite the sun from your point of view. In fact, everyone sees a unique rainbow."
- "The wake behind a duck on a pond always forms an angle of 39 degrees."
- "The metre is defined as one 10-millionth of the distance from the North Pole to the equator."

There were also moments in this book which made me laugh out loud - certainly not what I was expecting from this book on maths.

So all in all, this is acute book, and you should read it.

Thank you to Net Galley and Matt Parker for an advanced copy of this book in return for a fair and honest review.

[Chris · Rating 3 out of 5]

I love Matt Parker's YouTube content and I really though I would like this more. The book is written in Matt Parker's voice but it doesn't come across the same as he does in the visual medium. Also I think maybe I already know too much math for the target audience of this book. I was hoping to be challenged a bit more. Not a bad book at all, just not meant for me.

[Neka · Rating 5 out of 5]

This was an engaging read! As a STEM educator, I always scout for texts that break down complex subjects for the average reader. I recommend this book to anyone who wants a digestible and fun survey of the subject. Parker brought every day insight to concepts that I struggled with personally. I look forward to reading “Humble Pi”.

[Spencer Emmett · Rating 2 out of 5]

For a book titled as a love paean to triangles there is a surprisingly small amount of trigonometry here. In fact proper trigonometry is not even introduced until halfway through the book. This is more of a hodgepodge nerd fest about various math topics. Some like rainbow optics and honeycomb shapes I found interesting. Some like mesh codes for 3D printing and tiling patterns for polygons and solids felt tedious and/or over my head. If you love reading about complicated prisms with names like elongated pentagonal gyrobicupolarotunda (seriously there is an entire chapter of these), then have it. Also take a look at the weirdest index ever printed in the back of a book. Personally I would prefer thumbing back through one of my old high school math textbooks.