This TikTok teen uses math and photos to accurately guess strangers' heights 

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When University of Memphis student Kenyon Lee realized he was spending a lot of time on TikTok, he figured he should use some of it to create content of his own.

So when he spotted a TikTok user issuing a challenge to guess their height, he figured it would make for interesting content if he could solve that problem, and — like a good math student — show his work.

By the evening after he posted a response, his video had one million views. 

"I experimented with some other content, but every time I did a 'guess my height' video it just kept going up and up to the point where I did one video that got 17 million [views] in two or three days, and I was like, OK, I need to just adopt this as kind of my thing," Lee told As It Happens guest host Helen Mann. 

The 18-year-old engineering technology student has since become a TikTok sensation with 2.5 million followers and as many as 20,000 requests per day from people who want him to guess their height.

Lee calculates the height of strangers on the internet by looking through their social feeds for photos with objects that become frames of reference, and combines these with established facts and ratios about human anatomy.

"What I typically do is I try and find somebody's wingspan, which follows closely a one-to-one ratio with someone's height. And so typically I just find posts next to where people have, like, random objects in their pictures, and I use that to find their wingspans," Lee said.

Furniture, coffee cups and cheese slices

In one video he identified a dresser from IKEA, then using its height, estimated his subject's waist was about seven inches lower than the top of the dresser, then used a leg-to-torso ratio of one to 1.5 and an estimation of the length of her neck and head to determine the poster was about five feet two inches.

Lee has been refining his formula as he goes. In one big moment early on, he started to use ratios established by Leonardo da Vinci's Vitruvian Man, which illustrates proportions of the human body as calculated by architect Vitruvius Pollio. 

With that information, he's used everything from the circumference of the top of a coffee cup to a slice of processed cheese to determine length of hands and forearms, for instance.

As he tweaks his formulas, Lee's accuracy — which he pegs at about 90 per cent — has been improving.

"My past three to five videos have been, like, right on the dot."

Lee says it takes him between four and eight hours to make his calculations, then another one or two hours to create the corresponding video.

A number of influential mathematicians have weighed in on the comments of his videos to offer their support and verify his work.

Lee, who works with a tutoring company, said he hopes his videos both educate about the math he's using and promote the creativity that goes into this kind of problem-solving.  

He said he knows there are simpler ways to estimate people's height, but his methods are "way more entertaining for the viewer."

"And, you know, it's eye-opening for some of my younger crowd. It kind of motivates them to try and look at problems a different way, and actually try and hone their math skills," he said. 

The sleuthing involved in finding points of reference from stranger's social feeds has got Lee thinking about different career options.

"I've been looking into digital forensics," he said.

Since Lee can't make money from his videos on TikTok, he has started a YouTube channel to see if he can build a presence on a platform where he can potentially earn some cash to help fund his education.

While he's been approached by numerous potential sponsors, Lee said he's taking his time to assess what kind of promotional opportunities might align with his content.

For now he's simply having fun with this project.

"Other people just see this as just, like, you know, really crazy, like I'm just some big celebrity," he said. "But, I don't know, it's like a hobby to me."

Written by Brandie Weikle. Interview produced by Matt Meuse.