Question

In the accompanying diagram, PA is tangent to the circle at A and PC is a secant. If

PA = 8 and PB = 4, then BC =

Answer 1

c. 12

Explanation:

PA² = (BC + PB) × PB => tangent-secant theorem

PA = 8

PB = 4

BC = ?

Substitute

8² = (BC + 4) × 4

64 = 4BC + 16

64 - 16 = 4BC + 16 - 16

48 = 4BC

48/4 = 4BC/4

12 = BC

BC = 12