# Circles with radii 3, 4 and 5 touch each other externally if P is the point of intersection of tangents to these circles at their points of contact. Find the distance of P from the points of contact.

Arun Kumar IIT Delhi
$\\=>r=\Delta/s=\sqrt{(s-a)(s-b)(s-c) \over s} \\=>2s=7+8+9=24 \\=>s=12 \\r=\sqrt5$