Question

What is the area of a regular pentagon with a side length of 9 millimeters and an apothem length of 6.2 millimeters?

A. 55.8 millimeters squared
B. 279.0 millimeters squared
C. 27.9 millimeters squared
D. 139.5 millimeters squared

Answer 1

A Pentagon can be broken up into 5 equal triangles. Area of the Pentagon is the sum of all the 5 triangles.

Area of the pentagon = 5 ( 1/2 x 6.2 x 9) = 139.5 mm²

Answer: 129.5 mm² (Answer D)