Question

ΔABC is a right triangle and DB is the altitude to hypotenuse AC. If DB=10 cm and CD=20 cm, find AB.

Answer 1

The answer is \[
5\sqrt 5\]

Answer 2

\[ BD^2 = DC \times AD\]
This gives AD =5

Answer 3

\[
AB=\sqrt{ 5^2 + 10^2}= 5 \sqrt 5
\]