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

I answered this for you a few minutes ago.

http://www.jiskha.com/display.cgi?id=1355792620