The triangle below has a height of 12 feet and a base of 9 feet. What is the area of the triangle?
If the area of a square is 81 square meters which formula would you use to calculate the perimeter of the square?
The circumference of this circle is approximately 66 inches. What is the radius?
The first two are correct. Your last one isn't right.
C = pi * d
I don't know the diameter.
But you do know the circumference. And you know the value of pi.
Oh. Because I was using the formula radius=C/2 pi