Exercise 1 Page 448

We want to calculate the surface area of 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.A.=π r^2 + π rl We know that the slant height of the cone equals 13 meters and the radius equals 5 meters. By substituting r with 5 and l with 13 into the formula, we can calculate S.A.

S.A.= π r^2 + π rl

SubstituteII

r= 5, l= 13

S.A. = π( 5)^2 + π ( 5)( 13)

▼

Simplify right-hand side

CalcPow

Calculate power

S.A. = π (25) + π (5)(13)

Multiply

Multiply

S.A. = 25π + 65π

AddTerms

Add terms

S.A. = 90π

Let's now substitute 3.14 for π and round the result to the nearest tenth.

S.A. = 90π

Substitute

π= 3.14

S.A. = 90( 3.14)

Multiply

Multiply

S.A. = 282.6

The surface area of the cone is 282.6 square meters.