Circle A has a diameter of 8 inches, a circumference of 25.12 inches, and an area of 50.24 square inches. The diameter of circle B is 3 inches, the circumference is 9.42 inches, and the area is 7.065 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)
C =2pi*(d/2) A = pi (d/2)^2
Part A
A B
25.12 = 2pi *(8/2) 9.42 = 2pi (3/2)
25.12 = 8pi 9.42 = 3pi
pi = 25.12 / 8 pi = 9.42 / 3
pi ≈ 3.14 pi = 3.14
Part B
A B
50.24 = pi (8/2)^2 7.065 = pi (3/2)^2
50.24 = pi *4^2 7.065 = pi (9/4)
50.24 = 16 pi 7.065 ( 4/9) = pi
50.24/16 = pi pi = 3.14
pi = 3.14
Part C
We see that pi is the constant ≈ 3.14 (as we should expect )