Question

Red ribbons are wrapped around all the columns of a building. Each ribbon does not overlap itself. Each column has a radius of 3 feet. if all the ribbons are taken off the columns and attached end to end, they would measure 144 pi feet long. How many columns does the building have?
A)8
B)16
C)24
D)40
plzz help

Answer 1

Hello!

If this long ribbon measures 144$\pi$ feet, you can see, it was only multiplied by one number, which has the be the diameter of a column to get our circumference. If we divide this by our diameter 6 (diameter is double the radius, 3), we get our answer below.

144/6=24

Therefore, our answer is C) 24.

I hope this helps!

Answer 2

Length of a ribbon that is wrapped around 1 column = pi r^2 = 3^2 pi

= 9 pi feet

Number of columns = 144 pi / 9 pi

= 16 answer