 # Surface Area: Prisms and Cylinders

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Surface Area: Prisms and Cylinders
Lesson 11-4 Pages Surface Area: Prisms and Cylinders

What you will learn! How to find surface area of prisms.
How to find surface area of cylinders.

Vocabulary Surface 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 = 2r2 + 2rh

Find the surface area of the rectangular prism:
Example 1: Find the surface area of the rectangular prism:

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

S = 1, S = 1,868 cm2

Find the surface area of the triangular prism.
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. 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 = 2r2 + 2rh S = 2• •2.5•8 S = 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 wh S = 263 in2 S ≈ 197.9 in2 S = 2r2 + 2rh

Page 576 Guided Practice #’s 3-8

Pages 573-575 with someone at home and study examples!
Read: Pages with someone at home and study examples!

Homework: Pages #’s 9-18, 25, 26, 30, 31

Odd Answers in Back of Book!
Prepare for Mid-Test! Pages #’s 9-20 Odd Answers in Back of Book!

Page 751 Lesson 11-4

Page 576 # 11 10 m 9 m 6 m 8 m 8 m

Page 576 # 11 10 m 9 m 6 m 8 m 8 m