Answer:
In this diagram, we know that PB is tangent to the circle. This means that angle PAB is 90 degrees.
We also know that PA = 5 and PB = 10.
Using the Pythagorean Theorem, we can find the length of AB:
AB^2 = PA^2 + PB^2
AB^2 = 5^2 + 10^2
AB^2 = 125
AB = sqrt(125)
AB = 5sqrt(5)
Now, we can find the length of AC using the Pythagorean Theorem again:
AC^2 = AB^2 + BC^2
AC^2 = (5sqrt(5))^2 + (10)^2
AC^2 = 125 + 100
AC^2 = 225
AC = sqrt(225)
AC = 15
Therefore, the length of AC is 15.