Exercise 22 Page 637

The given solid is a cone.

To calculate the surface area of a cone, we can use the known formula where r is the radius of the base and l is the slant height of the cone. S=π rl+π r^2 Looking at the diagram, we know that the diameter of the cone's base is 7.8 centimeters. By dividing by 2, we get the radius of the base. r=7.8/2 ⇒ r = 3.9cm We are told that the slant height of the cone equals 15.8 centimeters. By substituting r with 3.9 and l with 15.8 into the formula, we can calculate S.

The surface area of the cone is approximately 241.4 square centimeters.