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Home > GC > Chapter 12 > Lesson 12.2.3 > Problem 12-77
12-77.
Find the area of the shaded region of the regular pentagon at right. Show all work.
Label the shaded region as
The measure of each angle in a pentagon is equal to
Therefore, the measure of
Divide
Solve for the length of AD:
Once you know the length of AD, use the formula (1/2)(Base)(Height) to find the area of the shaded triangle.