Name

Lesson Master

Objective C

In 1—3, find the area of the triangle.

1. 2.

0.80.6

1.3

o.gq

Objective H

Questions on SPUR Objectives

See Student Edition pages 511—515 for objectives.

3.7.5 34 128

4

8.5

—Il-Iza—————

4. Explain how the formula for the area of a right triangle is derived from

the formula for the area of a rectangle.

5. Use the picture of rectangle PQRS to explain why the area

of ASJR is L Jib.

s

USES Objective K

the side of a house has the dimensions shown.

b

In 6 and 7, Each window is 22 ft-by-3ä ft. 20 ft

6. Find the area of the shaded region.

22 ft

7. If each gallon of paint covers 250 square feet, how

many gallon paint cans do you need to buy to paint

the side of the house with two coats of paint?

REPRESENTATIONS Objective M

8. Find the area of triangle ABC with A = (0, 3), B = (6, 3), (4, 8). 15

9. How does the answer to Question 8 change if C = (8, 8)? Explain.

No ne

Geometry 455

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Name

Lesson Master

SKILLS Objective C

In 1—3, find the area of ABUG.

1.12

5

13

3.U 3y G 2YD

16

Area (ADUB) = 80

Answer Page

Questions on SPUR Objectives

See Student Edition pages 511—515 for objectives.

2.12 D 6

8

4. IfArea(ALON) — - 150 units2, find IN.

L 8 12

10 unit-S5. The two legs of a right triangle measure 8 cm and 25 cm. Find the

area of the triangle. IOC Cry) z

6. The area of a right triangle is 36 in2. If the length of one leg is 6 in.,what is the length of the other leg?

Objective H7. Explain how the formula for the area of a triangle can be derived from

the formula for the area of a parallelogram.

e

8. Given an isosceles right triangle with legs of length s, how manytimes as great is the area of an isosceles right triangle whose legs

9. How does the area of a triangle change if its base is doubled andits height is halved?

456 Geometry

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Name

8-4B

USES Objective K

10. The flag of Antigua and Barbuda shown at the right is a rectangle 3 feet

high and 4 feet wide. fie two shaded triangles are congruent. How

much material is needed for each shaded triangle?

11. The rectangular Congo flag pictured at the right is 225 cm wide and150 cm high. What percent of the flag is the stripe which is enclosedby the isosceles triangles?

33

12. The roof sections of the hexagonal gazebo at the right are shaped likecongruent isosceles triangles.

a. What is the total area of the roof?

b. What will be the cost for roof shingles if the price is $12.99 per

bundle and 3 bundles cover 100 square feet?

REPRESENTATIONS Objective M

13. A triangle has vertices (-5, 7), (4, 7), and (1, 2).

a. Draw the triangle on the grid at the right.

b. Find the of the triangle.

14. The three sides of a triangle are on the x-axis, the y-axis, and

the line with-equation 8x + 5y = 40. -5) Co

a. Draw the triangle on the grid at the right.

b. Find the area of the triangle.

Answer Page

page 2

10 ft

10 ft

x

Geometry 457

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Name

Lesson Master

Answer Page

Questions on SPUR Objectives

See Student Edition pages 511—515 for objectives.

CZÄ) Objective c1. Find the area of the

parallelogram below.

912

unfrs

2. Find the area of the

trapezoid below.

18.0

12.2

26.0

3. Find the area of the

rhombus below.

8

16.05

UnvY5

Objective K 2 ft4. Katie's Kite Factory makes nylon kites with the dimensions shown.

Assuming they can cut the material so there is no waste, how manycomplete kites can be made from a piece of material with anarea of 100 ft2?

5. A window seat in a bay window is in the shape of an isosceles

trapezoid. The window side of the seat is 36 inches long; the room

side is 64 inches long, and the seat is 16 inches deep. Find the

approximate area of the seat in square feet.

REPRESENTATIONS Objective M

6. Graph trapezoid PQRS with P = (1, -2), Q = (1, 7),

and S = (6, 0) and find its area.

35 x10

7. A parallelogram ABCD has coordinates A = (0,

(11, 9), and D = (3, 9). Find the area of parallelogram ABCD.

-10

458 Geometry

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Name

Lesson Master

SKILLS Objective C

Answer Page

Questions on SPUR ObjectivesSee Student Edition pages 511—515 for objectives.

st.

In 1-5, use the information in the drawing to find the area of the trapezoid.

12 16

18 16112

16.25

18

4vfiä

4.7

141,

In 6 and 7 find the area of trapezoid ABCD.

10 5.8

4.9

33, ga

8. A rhombus has a perimeter of 84 cm and an area of 252 cm2.

Find the length of the altitude.

9. An isosceles trapezoid has an area of 144 in2. Its altitude measures 9 in.

Give a possible combination of lengths for the bases of the trapezoid.

32

Geometry 459

Answer Page

Back to Lesson 8-5

Name

page 28-5B

USES Objective K

In 10 and 11, use the diagrams to estimate the area of the state.

Dimensions are given in miles.

10. 310 11.

NORTH TENNESSEE210 DAKOTA 40

360

L.II quo277 km

12. The Canadian province of Saskatchewan is shaped roughly like an

isosceles trapezoid whose dimensions, according to Saskatchewan's

Office of Central Survey and Mapping, are given on the map at the 773 km

right. Estimate the area of Saskatchewan.

393 km

13. A lawn-maintenance person can mow about 9,000 square feet

of grass per hour. At this rate, how long would it take for this 149 ft 210 ft

person to mow the plot of land at the right? 290 ft

00.5 b,-

126 ft

14. The tables in a pre-school classroom are shaped like isosceles 3 ftltrapezoids as shown at the right. 450

a. If two of these tables are placed with their longer bases

aligned, what shape is formed?

b. What is the combined area of the tables in Part a?

Ob j e ctive M

In 15 and 16, find the area of the region.

15. 16.

xx

8

57.5

460 Geometry