Question

A circle of radius greater than 9 cm is inscribed in the square ABCD. A point P on the circle is 8 cm from side AB of the square, and 9 cm from side AD. What is the radius of the circle?
D-----------C
| |
| | <---circle inscribed in it
| |
| |
A-----------B

Answer 1

sorry the square got messed up

Answer 2

that's ok -- we know what a square looks like.

Looks like we have

(r-8)^2 + (r-9)^2 = r^2