Question

suppose a ladder 20 feet long is placed against a vertical wall 20 feet high. How far would the top of the ladder move down the wall by pulling out the bottom of the ladder 5 feet?

Answer 1

You can use the pythagoras theorem.

20^2=5^2+x^2

x^2=400-25
x^2=375

x = 19.36

20-19.36=0.64 feet

The answer is 0.64 feet :)