Tightrope Across Town

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Tightrope Across Town

November 13, 2014

We always love hearing about people doing crazy stunts, like walking on a tightrope over a river between two really tall buildings — or better yet, a tightrope that runs uphill. Last week famed stunt man Nik Wallenda walked up a tightrope that stretched across the Chicago River from the Marina City west tower to the taller Leo Burnett Building about two blocks away. He started 588 feet off the ground at Marina City, and ended 671 feet high at Burnett, on a 454-foot long cable. As if that weren’t enough, Nik then took an elevator down to the street, went back to Marina City, and walked across a shorter tightrope while blindfolded, more than 500 feet above ground. Both record-breaking stunts were quick: less than 7 minutes for the first, and just over 1 minute for the second…because of the strong Chicago wind, Nik decided he’d better hurry up and finish before he fell off!

Wee ones: If Nik took about 7 minutes on the 1st tightrope and 1 minute on the 2nd, how many minutes did he spend walking in total?

Little kids: If the wind started blowing at 10 miles per hour but then sped up during the walk by 3 miles per hour, how fast did it get?  Bonus: If Nik took 7 minutes to do the 1st walk, 5 minutes to take the elevator down, 5 minutes to return to Marina City’s roof and 1 minute to do the 2nd stunt, how long did the whole event take?

Big kids: Which is more, Nik’s uphill tightrope walk or 1/10 of a mile? (Reminder: A mile has 5,280 feet.)  Bonus: If the trek started 588 feet high and ended 671 feet high, how many feet higher did Nik climb?

The sky’s the limit (literally): If the tightrope didn’t curve under Nik’s weight and he wanted to walk one twice as long from Marina City to another building, how tall would that building have to be?

 

 

 

Answers:
Wee ones: 8 minutes in total.

Little kids: 13 miles per hour.  Bonus: 18 minutes.

Big kids: A 1/10 of a mile, since that’s 528 feet – but his walk came close!  Bonus: 83 feet.

The sky’s the limit: 754 feet tall. This is the idea of congruent triangles: if one side of a triangle doubles to make a congruent triangle, then all sides double because all proportions remain the same to keep the same angles. The original triangle had a short side, or difference in height between the buildings, of 83 feet. So the new one would have to have a building difference of 166 feet. Adding that to Marina City’s height of 588 feet, that would give us a new finish-line height of 754 feet.

And a big thank-you to Mary Claire A. for sharing this story with us!

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About the Author

Laura Overdeck

Laura Overdeck

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.

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