Surface Area of Cones and Spheres

Surface Area of Cones and Spheres

Surface Area of Cones

• Find the area of the circle on the bottom of the cone using

   $\pi r^2$  

• Find the area of the side of the cone using  $\pi rl$  where r is the radius and l is the slant height of the cone.  

Example 1

Area of the circle.. $\pi r^2$ so (3.14)(6)(6)

+  $\pi rl$  so (3.14)(6)(10)=


301.44  $inches^2$ 

Multiple Choice

Find the surface area of the following cone.

• 113.04 cm squared

• 75.36 cm squared

• 128.74 cm squared

Multiple Choice

Find the surface area of the following cone.

• 157.2 yards squared

• 163.2 yards squared

• 252.58 yards squared

• 365.68 yards squared

Surface Area of Spheres

• To find the area of any sphere you just need to know the radius. The formula is: 

   $4\pi r^2$  

Example 1

Formula.. $4\pi r^2$ so (4) (3.14)(22)(22)=

6,079.04
 $cm^2$ 

Multiple Choice

Find the surface area of the following sphere.

• 452.16 mm²

• 108.8 mm²

• 904.32 mm²

• 6658.56 mm²

Multiple Choice

Find the surface area of the following cone.

• 314.16 in²

• 166.67 in²

• 314 in²

• 521.24 in²