Over Lesson 11–5

A. A

B. B

C. C

D. D

Find the measure of all angles.

Over Lesson 11-4

141 3x

54 2x

You found the area of rectangles. (PSSA Survivor)

• Find areas of parallelograms and triangles.

• Find areas of trapezoids.

• base

• altitude

The base of a parallelogram or a triangle is any side of the figure from which we measure the height. The bases of a trapezoid are the parallel sides.

A line segment that is perpendicular to the base of a figure with endpoints on the base and the side opposite that base. Often called the height.

Find Areas of Parallelograms

A. Find the area of the parallelogram.

The base is 3 meters.

The height is 3 meters.

A = bh Area of a parallelogram

A = 3 ● 3 Replace b with 3 and h with 3.

A = 9 Multiply.

Answer: The area is 9 square meters.

Find Areas of Parallelograms

B. Find the area of the parallelogram.

Estimate A = 4 × 6 or 24

The base is 4.3 inches.

The height is 6.2 inches.

A = bh Area of a parallelogram

A = 4.3 ● 6.2 Replace b with 4.3 and h with 6.2.

A = 26.66 Multiply.

Answer: The area is 26.66 square inches. This is close to the estimate.

A. A

B. B

C. C

D. D

A. 6 cm2

B. 7 cm2

C. 12 cm2

D. 14 cm2

A. Find the area of the parallelogram.

A. A

B. B

C. C

D. D

A. 0.975 ft2

B. 1.95 ft2

C. 2.8 ft2

D. 5.6 ft2

B. Find the area of the parallelogram.

Find Areas of Triangles

A. Find the area of the triangle.

Answer: The area of the triangle is 6 square meters.

The base is 3 meters.

The height is 4 meters.

Area of a triangle

Replace b with 3 and h with 4.

Multiply 3 × 4 = 12.

Simplify.

Find Areas of Triangles

B. Find the area of the triangle.

The base is 3.9 feet.

The height is 6.4 feet.

Area of a triangle

Replace b with 3.9 and h with 6.4.

Estimate

Find Areas of Triangles

Answer: The area of the triangle is 12.48 square feet.

Multiply 3.9 × 6.4.

Simplify.

Check 12.48 ≈ 12

A. A

B. B

C. C

D. D

A. 180 in2

B. 90 in2

C. 27 in2

D. 13.5 in2

A. Find the area of the triangle.

A. A

B. B

C. C

D. D A B C D

0% 0%0%0%

A. 4.4 cm2

B. 8.8 cm2

C. 9.36 cm2

D. 18.72 cm2

B. Find the area of the triangle.

Find Areas of Trapezoids

PLAYROOM The floor of a playroom is shaped like a trapezoid. Use the figure to find the area of the playroom.

Estimate

Find Areas of Trapezoids

Area of a trapezoid

Simplify inside parentheses.

Find Areas of Trapezoids

Simplify.

Answer: The area of the trapezoid is square meters.

Divide out the common factors.

Check

A. A

B. B

C. C

D. D

A. 20 ft2

B. 30 ft2

C. 40 ft2

D. 60 ft2

Find the area of the trapezoid.