﻿ ﻿SPHERES - Solid Geometry - SOLID AND COORDINATE GEOMETRY - SAT SUBJECT TEST MATH LEVEL 1

## SOLID AND COORDINATE GEOMETRY ## CHAPTER 12 Solid Geometry ### SPHERES

A sphere is the set of all points in space that are a fixed distance, r, from a given point, O. O is called the center of the sphere, and r is the radius.

The two formulas about spheres that you might need to use on the Math 1 test are those for volume and surface area. These two formulas, which are given to you in the “Reference Information” box, constitute the next KEY FACT. Key Fact K8

The formula for the volume of a sphere of radius r is .

The formula for the surface area of a sphere of radius r is A = 4πr2.

Remember

The formulas in KEY FACT K8 are listed in the Reference Information box on the first page of every Math 1 test.

EXAMPLE 7: What is the radius of a sphere whose surface area is equal to the surface area of a cube whose edges are 1?

By KEY FACT K2, the surface area of the cube is 6e2 = 6(1)2 = 6. Then by KEY FACT K8, ﻿