Rounded to the nearest ounce, Jack’s basketball weighs 22 oz. What is the

least and most it could weigh, in tenths of an ounce?

COURSE 1 LESSON 9-3

21.5 oz; 22.4 oz

9-3

Perimeters and Areas of Rectangles

In Lesson 9-2 you learned to convert between metric

measurements.

What You Learned

Introduction

pg 426-430

Pg 134-135 Daily Notetaking Guide

Materials:

Materials

In Lesson 9-3 you will learn to solve problems involving

perimeters and areas of rectangles

What You’ll Learn

Why Learn This?

The length of a fence around a figure is a different

measure from the area enclosed be the fence. You

need to know how to find both measures.

Introduction

Vocabulary

Perimeter – of a figure is the distance around the figure.

Area – of a figure is the number if square units the figure

contains.

Vocabulary

COURSE 1 LESSON 9-3

(For help, go to Lesson 4-2.)

1. Name the base and the exponent in 32.

Perimeters and Areas of Rectangles

9-3

Check Skills You’ll Need

Vocabulary Review

base: 3; exponent: 2

Simplify each expression

2. 42 42 = 4 4 = 16

3. 62 62 = 6 6 = 36

4. 5.42 5.42 = 5.4 5.4 = 29.16

5. 1.62 1.62 = 1.6 1.6 = 2.56

COURSE 1 LESSON 9-3

To renovate their bedroom, the Novaks are

carpeting the floor and pasting a wallpaper border along the

top of each wall. Find the perimeter and area of their

bedroom.

The length is 12 ft.

The width is 14 ft.

P = 2( + w) Use the formula for perimeter.

= 2(12 + 14) Substitute 12 for and 14 for w.

= 2 26 Add.

= 52 Multiply.

Perimeters and Areas of Rectangles

9-3

COURSE 1 LESSON 9-3

(continued)

The perimeter is 52 feet. The area is 168 square feet.

The length is 12 ft.

The width is 14 ft.

A = w Use the formula for area.

= 12 14 Substitute 12 for and 14 for w.

= 168 Multiply.

Perimeters and Areas of Rectangles

9-3

Quick Check

COURSE 1 LESSON 9-3

The perimeter of a square is 28 meters. Find its area.

Use the perimeter formula.

P = 4s

Use the area formula.

A = s2

= 72

= 49

The area of the square is 49 square meters, or 49 m2.

28 = 4s

=

7 = s

28

4

4s

4

Perimeters and Areas of Rectangles

9-3

Quick Check

What is the difference between the area of a figure and

the perimeter of a figure?

The area of a figure is the number of square units it

contains. The perimeter of a figure is the distance

around it.

Closure

9-3

How do you find the area and the perimeter of a

rectangle?

Area: Use the formula A= l x w (Area = Length x Width)

Perimeter: Use the formula P = 2(l + w) [Perimeter = 2 x

(Length + Width)]

Perimeters and Areas of Rectangles

Find the perimeter and area of each.

1. a square with sides that measure 25 mm

2. a rectangle with a length of 11 in. and a width of 8 in.

3. a rectangle with a width of 9 cm and a length of 27 cm

4. a square with a side of 13 ft

COURSE 1 LESSON 9-3

100 mm; 625 mm2

38 in.; 88 in.2

72 cm; 243 cm2

52 ft; 169 ft2

9-3

Class work

pg 429 – 430 1 - 30

Homework

pg 387 Practice 9-3

pg 388 Guided Problem Solving 9-3

Work