The shaded region is the area of the circle minus the area of the pentagon. A circle = pi * r^2 A circle = pi * 15^2 A circle = 706.5 cm^2
A regular pentagon = (a * p)/2 where a is the apothem, p is the perimeter. The apothem id the perpendicular height from the midpoint of a side to the center of the pentagon. To find the apothem you have to use a trig ratio. A pent = (8.3 * 12*5)/2 A pent = 249 cm^2
Shaded region: circle - pentagon 706.5 - 249 = 457.5
