Math
posted by Marco .
A 20 meter ladder is leaning against a house.The bottom of the ladder is 15 meters away from the house. How far, to the nearest tenth, is the top of ladder from the ground?
Do I multiply 20,x 15?
I don't know how to do the problem

Since you're trying to find one leg of a right triangle, you need to use the Pythagorean Theorem. The ladder is the hypotenuse of this triangle.
a^2 + b^2 = c^2
15^2 + b^2 = 20^2
225 + b^2 = 400
b^2 = 175
b = 13.228 = 13.2 meters