Question

ali has a modle of earth that has a diameter of 12 centimeters. ehat is the serface area of this modlel

Answer 1

For reasons that might eventually be proven in a later calculus course, the surface area of a sphere is given by the formula

A = 4r²π

or, since the radius r is half of the diameter d (d = 2r):

A = d²π

Since our diameter is 12 cm, the area would then be

12²π = 144π cm²

Answer 2

The surface area of the model is 144π cm.²

To find the surface area of the sphere, we need to know the formula for the surface area of a sphere. The formula for the surface area of a sphere is 4πr². But, we don't have the radius! We only know the diameter. But, since the d is equal to twice the radius, if the diameter is 12, the radius is 12/2 or 6. Now we can solve.

4 * π * (6)²=

=4 * π * 36=

=144π

That means that the surface area of the model is 144π cm.²