2

Part of 1981 Poland - Second Round

Problems(1)

angle bisector wanted, 2 internally tangent circles

Source: Polish MO Recond Round 1981 p2

Two circles touch internally at point

P

. A line tangent to one of the circles at point

A

intersects the other circle at points

B

C

. Prove that the line

PA

is the bisector of the angle

BPC

geometryangle bisectorcircles