Examine the following diagram, where AP¯¯¯¯¯¯¯¯

is secant to the circle at points A
and B,
and CP¯¯¯¯¯¯¯¯
is secant to the circle at points C
and D.
The lines intersect outside the circle at point P.

A circle, with no center shown, and two secants, segment A P and segment C P, as described in the text. Segment A B equals 8, segment B P equals 10, and segment C P equals 20. What is the length of PD¯¯¯¯¯¯¯¯?
Responses

9
9

11
11

12
12

7