A few questions about the circle.

1. Is the circumference the perimeter of a circle?

2. Why is pi part of the formula C = pi•d?

3. Can we say that C = pi•d is the same as

C= (22/7)(d)?

4. The area of a circle is given by A = pi•r^2. Can this formula also be expressed as C = pi•(d/2)^2, where d is the diameter?