Page 260 - ABCTE Study Guide_Neat

Question

What is the surface area of sphere with diameter 8 yd? Round your answer to the nearest square yard.

2
A 50 yd

2
B 101 yd

2
C 201 yd

2
D 804 yd

Answer

Choice C is the correct answer. The surface area of the sphere is given by the formula , where r =
4 yd. The sphere has surface area equal to

If you picked choice D, you may have used 8 yd for the value of the radius rather than the value of the
diameter. Remember, everything about a sphere depends on its radius, so the most common way to mix
up a circle or sphere problem is to give the diameter instead of the radius. Please be careful.

Got your fill of formulas yet? The surface area formulas for polyhedra are quite intuitive; the surface area
formula for a cone is not. Or is it?

Volume

Cylinders

Recall that the volume of a prism is , where B is the area of the base and h is the height. The same
is true for cylinders, except now the base is a circle. So .