SA and V review before test Question: 7

Question

If a sphere has a circumference of 75.36 ​in., what formula should you use to find the​ radius? What is the surface area of the​ sphere?

Let C=2πr equal the fourmula for the radius of the sphere

The surface area of the spherical object is about ____________ in.2.

​(Type an integer or decimal rounded to the nearest hundredth as​ needed.)

Answer 1

volume of sphere = 4/3 pi (r cubed)

surface area of a sphere = 4 pi (r squared)

75.36 = 2pi(r)

r = 75.36/2pi = about 75.36/2(3.14159) = 12

surface area = 4pi(12^2) = 4(144)pi = 576(3.14159)= = 1809.6 square inches