# This TikTok Genius Will Guess Your Exact Height Using Math

Courtney Linder

From Popular Mechanics

• Kenyon Lee, who runs the TikTok account @kentai.haven, has an uncanny knack for guessing people's heights with a little bit of internet sleuthing and a whole lot of math.

• He's amassed 2.5 million followers in four weeks.

• One day, he hopes to outline his process in an academic research paper.

The 18-year-old University of Memphis student will stalk your social media posts until he finds "evidence," sleuth around to compare your arms and hands to other objects in the background, analyze each video frame by frame, and ultimately use math to calculate your height.

It may take Lee upward of 8 hours to do it, but he's dedicated, and his 2.5 million followers on TikTok simply won't rest until he has figured out how tall every person is on the planet.

We know: That sounds pretty intense. But it's the basis for the extremely popular viral videos on Lee's TikTok account, @kentai.haven. About four weeks ago, he posted his first video, in which he tried to guess the height of another TikTok user by relying solely on a stool in her room and the average measurements for two human bones in the leg, the femur and tibia. Lee guessed she was about 5 feet tall—and he was correct.

Lee went to bed with 30 followers and woke up with over 1 million views and an idea to capitalize on his newfound fame. “I felt famous," he tells Popular Mechanics, "but now I’ve gotten over 800,000 followers in one day.”

At the height of his popularity, Lee says his mentions were blowing up, with 10,000 to 20,000 TikTokers tagging him in people's videos each day, begging him to guess their height with his unorthodox method. So how does he decide which videos to ultimately follow up on?

“If I go on my mentions, and I see it’s all the same video—it’s viral—I jump on it. Sometimes a celebrity will challenge me, specifically, and if I’m not too busy, I try to coordinate with them, but I always keep it organic," Lee says. "Some people think I have them tell me their heights, but they don’t."

While Lee isn't ready to give away all of his secrets—including the special formulas he's developed to determine people's height—he will reveal some of his process. He uses linear algebra, geometry, calculus, some statistics, and basic rules about human anatomy.

Step one: scroll all the way to the bottom of the person's TikTok profile, and start watching all of their videos until you find a good piece of "evidence," Lee explains. If the person has other social media accounts, like YouTube, he'll watch hours of those videos, too.

This sleuthing is the most time-consuming part of the process, because Lee must find references that will help him to determine the distance between the person's elbow to the top of their middle finger. Or he uses an object they're holding to calculate their hand size.

It all boils down to the "golden ratio," or the "golden number," Lee says. Phi, which is represented by the Greek symbol Φ, is 61803399. It has unique geometrical properties, as noted in early writings by the Greek mathematician Euclid (the "father of geometry") around 300 B.C.

One of the most famous examples of this is in the Fibonacci sequence, a series of numbers in which each is the sum of the two numbers that precede it. In this sequence of numbers—0, 1, 1, 2, 3, 5, 8, 13, 21, 34—that rule holds true. Examples of this abound in nature, specifically in phyllotaxis, or the study of how leaves, branches, flowers, or seeds arrange themselves. In a sunflower, for instance, the seeds at the center of the flower are arranged along curved lines that rotate clockwise and counterclockwise, creating a spiral.

While it may not seem like a spiral at the center of a flower has anything to do with a person's height, that same golden ratio can be used to describe the ratio between the height of a human adult and that of their navel, or the length of their forearm compared to that of their hand.

This isn't a hard-and-fast rule, of course, and some mathematicians say these kinds of applications of the golden number are based in myth.

Lee also considers the standard human ratio for wingspan is 1:1 with their height, meaning your outstretched arms, from right index finger to left index finger, should be the same length as your height. "It can go up to a 7 percent difference," Lee says, "but I take that gamble."

For example, when Lee did a video on a basketball player, he added in the average height index for NBA players and subtracted that from the wingspan, correctly guessing the man's height.

In 30 videos, Lee has only gotten three or four people's heights wrong, giving him an accuracy of about 90 percent.

At the moment, Lee is pretty busy with his studies, but he's managed to carve out some spare time to learn even more math in the evenings. As he accumulates more knowledge, he hopes he'll be able to perfect his formulas even more. (That's some of his methodology on the whiteboard above.)

As Lee put these equations together, he searched through academic journals and couldn't find any peer-reviewed research that comes near his methodology. He hopes to one day accumulate more data by getting the heights for a few thousand people and running with his method until he gets a more accurate average for his rules.

Even if that doesn't work out, Lee plans to put his math skills to use. He says he'd like to become an engineer one day, or perhaps pursue computer science.

But until then, he's perfectly content with being known as the "height guy" on TikTok.

"I have no problem with it," Lee says. "That’s when you know you’ve made it—when people can just use a few words to describe you and they know who you are. I want to be the CEO of guessing everything.”

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