Area of Inscribed Circle

The perimeter and area of a triangle are 20 inches and 12 square inches, respectively. What is the area in square inches of a circle inscribed in the triangle?
Source: NCTM Mathematics Teacher, February 2006

area of AIB=(1/2)cr\qquad (1)
area of BIC=(1/2)ar\qquad (2)
area of AIC=(1/2)br\qquad (3)
Add all three equations
area of ABC=(1/2)r(a+b+c)
Area of inscribed circle

Answer: 1.44\pi square inches


About mvtrinh

Retired high school math teacher.
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