Answer:
P = 12 pi units + 24 units.
Step-by-step explanation:
All sides of an equilateral triangle are of the same length. Here that length is 12 units. We take a circle of diameter 12 units and cut it in half through its center. Finally, we join the triangle (remembering that all of the side lengths are 12 units) to the half circle of diameter 12 units.
The half circle portion of the resulting shape has circumference 2(pi)(12 units) divided by 2, or 12 pi units. This is half the formula C = 2(pi)(r). The two non-attached sides of the triangle have a total length of 24 units.
Thus, the perimeter of the resulting figure is P = 12 pi units + 24 units.
