Question

AC = 36 and BC = 18, find AD.

Answer 1

Theorem: If an altitude is drawn to the hypotenuse of a right triangle, either leg of the triangle is the geometric mean between the length of the hypotenuse and the segment of the hypotenuse adjacent to that leg.

Answer 2

http://www.mathwarehouse.com/geometry/similar/triangles/geometric-mean.php similar right triangles
you can set up proportion

Answer 3

hyp /Leg (outer triangle ) = hyp/side (smaller triangle)

Answer 4

hyp= hypotenuse