6th Grade Math Textbook, Fundamentals

Lesson 2-9 for exercise sets. &KDSWHU 

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Solve for the missing value. Use the volume, perimeter, and area formulas.

1.Find Vwhen 6 ft, 2.Find wwhen A117 in.^2 3.Find when P48 cm

w3 ft, and h9 ft. and 9 in. andw6 cm.

4.Discuss and Write GivenVwh, describe the steps for finding the height

if you know the values for V, , andw. Show the steps to justify your answer.

Find when P28 in. and w8 in.

Solve:P 2  2 w

28  2 2(8) Substitute the known values.

28  2  16 Simplify.

28  16  2  16  16

12  2 

12  2  2  2

6 

So the length is 6 in.

Use the Division Property

of Equality.

Use the Subtraction

Property of Equality.

2

Find wwhen A55 mm^2 and 11 mm.

Solve:Aw

55  11 w Substitute the known values.

 Use the Division Property of Equality.

5 w

So the width is 5 mm.

11 w

11

55

11

3

Find when A42 ft^2 and w3 ft.

Solve:Aw

42 • 3 Substitute the known values.

42  3  3  3

14 

So the length is 14 ft.

Use the Division Property

of Equality.

4

For Examples 3 and 4, use the formula for the area of a rectangle.



8 in.

Check: 28  2 2 • 8

28 2 • 6 2 • 8

28 12  16

28  28 Tr u e

? Substitute

? 6 for .



Remember:

Area of a

Rectangle:

Aw

w

11 mm

Check: 55 11 • w

55 11 • 5 Substitute 5 for w.

55  55 Tr u e

?



3 ft

Check: 42 • 3

42 14 • 3 Substitute 14 for .

42  42 Tr u e

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