3. A circle of radius 20 with center at point $O$ and a circle of radius 8 touch internally at point $H$. The line $X H$ is their common tangent, and the line $O X$ is tangent to the smaller circle. Find the square of the length of the segment $O X$.
Answer: 720

## Examples of how to write answers:

17

$1 / 7$

1.7