Math Pythagorean theorem

Question

A painter stes a ladder against a wall 9 ft above the ground. If the ladder is 3 feet from base of the wall, how long is the ladder?

Answer 1

Use the Pythagorean Theorem, hypotenuse squared = sum of squares of the other two sides

L^2 = 9^2 + 3^2 = 81 + 9 = 90

L = sqr90 = 3sqr10

L = about 9,49 feet