Five-Minute Check (over Lesson 11–1)

Main Idea

Key Concept: Area of a Triangle

Example 1:Find the Area of a Triangle

Key Concept: Area of a Trapezoid

Example 2: Find the Area of a Trapezoid

Example 3:Real-World Example

• Find the areas of triangles and trapezoids.

Find the Area of a Triangle

Find the area of the triangle below.

A = 14.4 Multiply.

Estimate

Find the Area of a Triangle

Answer: The area of the triangle is 14.4 squarecentimeters.

1. A

2. B

3. C

4. D

A B C D

0% 0%0%0%

A. 10.5 ft2

B. 13.5 ft2

C. 21.75 ft2

D. 27 ft2

Find the area of the triangle to the right.

Interactive Lab: Area of Trapezoids

Find the Area of a Trapezoid

Find the area of the trapezoid below.

The bases are 4 meters and 7.6 meters. The height is 3 meters.

Find the Area of a Trapezoid

Replace h with 3, b1 with 4, and b2 with 7.6.

Answer: The area of the trapezoid is 17.4 square meters.

1. A

2. B

3. C

4. D0% 0%0%0%

A. 26.5 cm2

B. 60.5 cm2

C. 61.5 cm2

D. 73.5 cm2

Find the area of the trapezoid to the right.

GEOGRAPHY The shape of the state of Montana resembles a trapezoid. Find the approximate area of Montana.

Answer: The area of Montana is about 145,493 square miles.

Replace h with 285, b1 with 542, and b2 with 479.

1. A

2. B

3. C

4. D0% 0%0%0%

A. 75 ft2

B. 150 ft2

C. 300 ft2

D. 450 ft2

PAINTING The diagram is of a canvas resembling a trapezoid that will be painted. In order to determine how much paint will be needed, estimate the area of the canvas in square feet.

End of the Lesson

Five-Minute Check (over Lesson 11–1)

Image Bank

Math Tools

Area of Trapezoids

Drawing 3-D Figures

Area of Polygons

1. A

2. B

3. C

4. D

A B C D

0% 0%0%0%

(over Lesson 11-1)

A. 209 in2

B. 198 in2

C. 99 in2

D. 60 in2

Find the area of the parallelogram. Round to the nearest tenth if necessary.

1. A

2. B

3. C

4. D

0% 0%0%0%

(over Lesson 11-1)

A. 19 yd2

B. 38 yd2

C. 42 yd2

D. 84 yd2

Find the area of the parallelogram. Round to the nearest tenth if necessary.

1. A

2. B

A B

0%0%

(over Lesson 11-1)

Determine whether the following statement is true or false. The height of a parallelogram is the distance from the base to the opposite side.

A. true

B. false

1. A

2. B

3. C

4. D

A B C D

0% 0%0%0%

(over Lesson 11-1)

A. 28 cm

B. 32 cm

C. 31 cm

D. 30.5 cm

What is the height of a parallelogram if the base is 24 centimeters and the area is 744 square centimeters?