10-1 Area of Rectangles and Parallelograms Warm Up Warm Up Lesson Presentation Lesson Presentation...
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Transcript of 10-1 Area of Rectangles and Parallelograms Warm Up Warm Up Lesson Presentation Lesson Presentation...
10-1 Area of Rectangles and Parallelograms
Warm UpWarm Up
Lesson Presentation
Problem of the Day
Lesson Quizzes
10-1 Area of Rectangles and Parallelograms
Warm Up
1. What is the perimeter of a square with side lengths of 15 in.?
2. What is the perimeter of a rectangle with length 16 cm and width 11 cm?
60 in.
54 cm
10-1 Area of Rectangles and Parallelograms
Problem of the Day
Two wibbles equal four wabbles, and eight wabbles equal two bibbles. If a square has a perimeter of 16 wibbles, what is its area in square bibbles?
4 square bibbles
10-1 Area of Rectangles and Parallelograms
Learn to estimate the area of irregular figures and to find the area of rectangles and parallelograms.
10-1 Area of Rectangles and Parallelograms
Vocabulary
area
10-1 Area of Rectangles and Parallelograms
The area of a figure is the amount of surface it covers. We measure area in square units.
10-1 Area of Rectangles and Parallelograms
Additional Example 1: Estimating the Area of an Irregular Figure
Find the area of the rectangle.
Count full squares: 19 red squares.
Count almost-full squares: 9 blue squares.Count squares that are about half-full: 4 green squares = 2 full squares.Do not count almost empty yellow squares.Add. 19 + 9 + 2 = 30
The area of the figure is about 30 mi .2
10-1 Area of Rectangles and Parallelograms
Check It Out: Example 1
Estimate the are of the figure.
Count full squares: 11 red squares.
Count almost-full squares: 5 green squares.Count squares that are about half-full: 4 blue squares = 2 full squares.Do not count almost empty yellow squares.Add. 11 + 5 + 2 = 18
The area of the figure is about 18 mi2.
= mi2
10-1 Area of Rectangles and Parallelograms
10-1 Area of Rectangles and Parallelograms
Additional Example 2: Finding the Area of a Rectangle
Find the area of the figure.
Write the formula.
Substitute 15 for l.Substitute 9 for w.
A = lw
A = 15 • 9
A = 135
The area is about 135 in2.
15 in.
9 in.
10-1 Area of Rectangles and Parallelograms
Check It Out: Example 2
Find the area of the figure.
Write the formula.
Substitute 13 for l.Substitute 7 for w.
A = lw
A = 13 • 7
A = 91
The area is about 91 in2.
13 in.
7 in.
10-1 Area of Rectangles and Parallelograms
You can use the formula for the area of a rectangle to write a formula for the area of a parallelogram. Imagine cutting off the triangle drawn in the parallelogram and sliding it to the right to form a rectangle.
The area of a parallelogram = bh. The area of a rectangle = lw.
The base of the parallelogram is the length of the rectangle. The height of the parallelogram is the width of the rectangle.
10-1 Area of Rectangles and Parallelograms
Additional Example 3: Finding the Area of a Parallelogram
Find the area of the parallelogram.
Write the formula.
Multiply.
A = bh
2 ft12
A = 2 • 112__ 1
4__ Substitute 2 for b
and 1 for h.
12__
14__
A = •52__ 5
4__
A = or 325 8
___ 18__
The area is 3 ft2. 18__
14
1 ft
10-1 Area of Rectangles and Parallelograms
Check It Out: Example 3
Find the area of the parallelogram.
Write the formula.
Multiply.
A = bh
A = 1 • 312__ 1
2__ Substitute 1 for b
and 3 for h.
12__
12__
A = •32__ 7
2__
A = or 521 4
___ 14__
The area is 5 ft2.14__
11 ft2
13 ft2
10-1 Area of Rectangles and Parallelograms
Additional Example 4: Recreation Application
Jessika is going to tile a kitchen that measures 13 ft by 17 ft. Some floor space is taken up by an island that measures 3 ft by 6 ft. How much area remains to be tiled in the kitchen?
Substitute for l and w in A = lw.
Use the order of operations.
The area of the kitchen to be tiled is 203 ft2.
floor area
To find the area to be tiled, subtract the area of the island from the area of the floor.
kitchen area to be tiledisland– =
(13 • 17) (3 • 6) n– =
221 – 18 = 203
10-1 Area of Rectangles and Parallelograms
Check It Out: Example 4
Miguel is going to landscape his backyard that measures 16 ft by 11 ft. Some of the backyard space is taken up by a built-in BBQ that measures 2 ft by 4 ft. How much area remains to be landscaped?
Substitute for l and w in A = lw. Use the order of operations.
The area of the backyard to be landscaped is 168 ft2.
backyard area
To find the landscaped area, subtract the area of the BBQ from the area of the backyard.
landscaped areaBBQ– =
(16 • 11) (2 • 4) n– =
176 – 8 = 168
10-1 Area of Rectangles and Parallelograms
Standard Lesson Quiz
Lesson Quizzes
Lesson Quiz for Student Response Systems
10-1 Area of Rectangles and Parallelograms
Lesson Quiz
Find the area of each figure.
1. 2.
3. What is the area of a parallelogram with base 16
in. and height 10 in.?
4. A square fish pond that is 6 ft long is
surrounded by a square walk that is 18 ft long.
What is the area covered by the walk?
41.4 m2 48 ft2
160 in2
288 ft2
10-1 Area of Rectangles and Parallelograms
1. Find the area of the figure.
A. 53.9 m2 B. 53.9 m2
C. 54.6 m2 D. 54.9 m2
Lesson Quiz for Student Response Systems
10-1 Area of Rectangles and Parallelograms
2. Find the area of the figure.
A. 60 ft2 B. 70 ft2
C. 80 ft2 D. 90 ft2
Lesson Quiz for Student Response Systems
10-1 Area of Rectangles and Parallelograms
3. Find the area of a parallelogram with base 19 ft and height 11 ft.
A. 209 ft2 B. 214 ft2
C. 216 ft2 D. 220 ft2
Lesson Quiz for Student Response Systems