Question

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.

Part B: Use the formula for area and solve for the value of pi for each circle.

Part C: What observation can you make about the value of pi for circles A and B?

Answer 1

A. The circumference is (pi)d where d is the diameter. So (pi) for circle A is 21.98/7=3.14 and for B is 18.84/6=3.14.

B. Area is (pi)r^2 where r=radius or d/2. So for circle A (pi)=38.465/(3.5)^2=3.14 and circle B (pi)=28.26/(3)^2=3.14.

C. To two places of decimals (pi) has a value of 3.14 in all cases. This indicates or implies that (pi) is a universal constant applying to all circles using the formulae.

Explanation: