Lesson 11-3 Pages 568-572

Volume: Pyramids and Cones

What you will learn!

1. How to find volume of pyramids.

2. How to find volume of cones.

ConeCone

What you really need to know!

To find the volume V of a pyramid, use the formula V = 1/3 Bh, where B is the area of the base, and h is the height of the solid.

What you really need to know!

To find the volume V of a cone, use the formula V = 1/3 r2h, where r is the radius of the base, and h is the height of the solid.

Link to Pre-Made Lesson

Example 1:

Find the volume of the pyramid. If necessary, round to the nearest tenth.

BhV3

1

1215153

1V

3900inV

Example 2:

Find the volume of the pyramid. If necessary, round to the nearest tenth.

BhV3

1

Base are 19 cm2

Height 21 cm

Base are 19 cm2

Height 21 cm

21193

1V

Base are 19 cm2

Height 21 cm

3133cmV

Example 3:

Find the volume of the cone. If necessary, round to the nearest tenth.

hrV 2

3

1

Example 3:

Find the volume of the cone. If necessary, round to the nearest tenth.

85.53

1 2 V

Example 3:

Find the volume of the cone. If necessary, round to the nearest tenth.

34.253 mV

Example 4:

When mulch was dumped from a truck, it formed a cone-shaped mound with a diameter of 15 feet and a height of 8 feet. What is the volume of the mulch? Round to the nearest whole number.

hrV 2

3

1

85.73

1 2 V

3471 ftV

Example 4b:

How many square feet can be covered with this mulch if 1 cubic foot covers 4 square feet of ground?

4 x 471 = 1,884 ft2

Page 570

Guided Practice

#’s 4-9

Pages 568-570 with someone at home and

study examples!

Read:

Homework: Pages 571-572

#’s 10-23, 27-34

Practice Quiz 1 #’s 1-5

Page

751

Lesson 11-3