Posted by Alyssa on .
A 20 foot ladder is leaning aagainst a wall the base of the ladder is 7 feet away from the.wall hkw high up the wall will the ladder reacb

Geometry 
Lena,
If you can imagine it, the figure will look like a right angle triangle. The hypotenuse will the 20 feet. The base will be 7 feet. The height is the unknown.
a^2 + b^2 = c^2
7^2 + b^2 = 20^2
Solve for 'b' and you will get the height of the wall where the ladder reaches.