20. Find the area of a circle inscribed in a 9-12-15 triangle.

(Hint: What kind of triangle is this?)

A = 176.7 units²

Step-by-step explanation:

Put the hint to use. Do these side lengths reflect the Pythagorean Theorem?

9^2 + 12^2 = 15^2?

81 + 144 = 225? YES

Therefore, this is a right triangle, and the diameter is 15 units.

Thus, the radius is 15/2 units, and the area is A = πr², or

A = π (15/2 units) ² = (225/4) π units². Using 3.14 for π, we get:

A = 176.7 units²