Solution:
Given the figure below:
The area of the shaded region is expressed as
step 1: Evaluate the area of the semicircle.
The area of the semicircle is expressed as
Thus, we have
step 2: Evaluate the area of the triangle.
The area of the triangle is expressed as
step 3: Evaluate the area of the shaded region.
Recall that
Thus, we have
Hence, the area of the shaded region is