Lesson 11-4 Pages 573-577

Surface Area: Prisms and Cylinders

What you will learn!

1. How to find surface area of prisms.

2. How to find surface area of cylinders.

Surface areaSurface area

What you really need to know!

To find the surface area S of a rectangular prism with length l, width w, and height h, use the formula:

S = 2lw + 2lh + 2wh.

What you really need to know!

To find the surface area S of a triangular prism, find the area of each face, then add to find the total surface area.

What you really need to know!

To find the surface area S of a cylinder with radius r and height h, use the formula:

S = 2r2 + 2rh

Link to Pre-Made Lesson

Example 1:

Find the surface area of the rectangular prism:

S = 2lw + 2lh + 2 whS = 2•34•21 + 2•34•4 + 2•21•4

S = 1,428 + 272 + 168

S = 1,868 cm2

Example 2:

Find the surface area of the triangular prism.

A triangular prism is made up of 2 triangles and 3 rectangles.

Example 2:

Find the surface area of the triangular prism.

192 + 60 + 48 + 36

2(½ x 12 x 16) + (20 x 3) + (16 x 3) + (12 x 3)

336 m2

Example 3:

Find the surface area of the cylinder. Round to the nearest tenth.

S = 2r2 + 2rhS = 2•2.52 + 2•2.5•8

S = 164.9 m2

Example 4:

A company packages its cereal in a rectangular prism that is 2.5 in. by 7 in. by 12 in. It is considering packaging it in a cylinder-shaped container having a 6-in. diameter and a height of 7.5 in. Which uses the least amount of packaging?

S = 2lw + 2lh + 2 whS = 2(12•2.5) + 2(12•7) + 2(2.5•7)

S = 263 in2

S = 2r2 + 2rh

S = 2•32 + 2•3•7.5

S ≈ 197.9 in2

Page 576

Guided Practice

#’s 3-8

Pages 573-575 with someone at home and

study examples!

Read:

Homework: Pages 576-577

#’s 9-18, 25, 26, 30, 31

Prepare for Mid-Test!

Pages 595-597

#’s 9-20Odd Answers in Back of Book!

Page

751

Lesson 11-4

Page 576

# 11

9 m

10 m

6 m

8 m

8 m

Page 576

# 11

9 m

10 m

6 m

8 m

8 m