Circle a has a diameter of 7 inches, a circumference of 21. 98 inches, and an area of 38. 465 square inches. The diameter of circle b is 6 inches, the circumference is 18. 84 inches, and the area is 28. 26 square inches. Part a: using the formula for circumference, solve for the value of pi for each circle. (4 points) part b: use the formula for area and solve for the value of pi for each circle. (4 points) part c: what observation can you make about the value of pi for circles a and b? (2 points).