@K311Y,
Quote:Ok, you've totally lost me.
Okay, you see the Math Forum page with the triangle, right?
This is what you get when you unroll the cylinder, like a toilet paper tube. The diagonal line, called the hypotenuse, is the string that wrapped around the cylinder, just like the indentation you see on the toilet paper tube before you unroll it.
The bottom of the triangle is 16 times around the cylinder, since we are told that the string wraps around the cylinder 16 times. The distance around the cylinder is the circumference, or PI times the diameter.
Now, the Pythagorean Theorem is a rule in math that says if we have a right triangle, we can take the square of each side and the sum of the squares of the two shorter sides (the right side and the bottom side) will equal the square of the long side (the diagonal side). This is often written as A^2 + B^2 = C^2, where ^2 means squaring (since the BBCode doesn't support superscripts).
The total height of the cylinder is just the right side of the triangle, so if I call the bottom A, the right side B and the diagonal C, then I want to calculate the square root of C^2 - A^2 to get B, the height of the cylinder.
I hope that helps.