SAT SUBJECT TEST MATH LEVEL 1
SOLID AND COORDINATE GEOMETRY
CHAPTER 12 Solid Geometry
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.
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,