Let's go over these formulas one more time.
Formulas for different shapes:
a = apothem
P = perimeter
Find the area of a circle with a diameter of 3 inches.
Hint
the radius is half the diameter
Answer
Find the area of:
the perimeter will be five times the length of a side
the bases make 90° angles with the height
This isosceles right triangle:
the base makes a 90° angle with the height
10.58 cm^{2}