posted by gabriela .
A candy cane 20 cm high has a circumference of 3 cm. The red “ribbon” makes exactly 4 complete turns round the candy cane while its two ends touch the cane's top and bottom. How long is the ribbon in cm?
Visualize the candy cane made in the form of a paper cylinder.
Cut the cylinder open, you will see that the "ribbon" around the candy cane or cylinder consists of 4 diagonals for 4 different rectangles.
the height of each of those rectangles is 20/4 or 5 cm
and the width is 3 cm
So the diagonal or hypotenuse is ..
√(5^2 + 3^2) = √34
So the length of the "ribbon" is 4√34