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Home > CCG > Chapter 12 > Lesson 12.2.3 > Problem 12-86

12-86.

Find the area of the shaded region of the regular pentagon at right. Show all work. Homework Help ✎

pentagon

Label the shaded region as ΔABC.

The measure of each angle in a pentagon is equal to .

Therefore, the measure of  is equal to 

Divide into two triangles. Use a trigonometric ratio to solve for .

units