Question

A lamp shade has a radius of 9 inches. What is the circumference of the top of the shade? Use 3.14 to approximate pi. Round your answer to the nearest whole number.

Answer 1

Circumference is diameter times pi, diameter is radius times 2.  The answer should be 57 inches.

Answer 2

C=2πr
or
C=πd

C=2×3.14×9
C≈56.52 inches, now we just need to round it up to get 57 inches. As a result, the circumference of the top of the shade is 57 inches. Hope it help!