Area of a rhombus

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NEO Thu, Feb 03, 2022 11:32 AM UTC

This pdf shows how to find the area of Rhombuses and similarity between rhombus and parallelograms with examples.

1. Reteaching
12-2
Area of Parallelograms
and Rhombuses
Find the area of this parallelogram. Find the area of this rhombus.
h 4 cm
h 6 in.
b 5 cm
b 8 in.
Use the formula A 5 bh. Use the formula A 5 bh.
A5836 A5534
2
A 5 48 in A 5 20 cm2
The area of the parallelogram is 48 sq in. The area of the rhombus is 20 cm2.
Find the area of each parallelogram or rhombus.
1. 2.
100 ft 7m
50 ft 12 m
2 2
5,000 ft 84 m
3. Rhombus: b 5 6 ft, h 5 4 ft 24 ft2
4. Parallelogram: b 5 18 m, h 5 13.5 m 243 m2
5. Parallelogram: b 5 20 in., h 5 9 _12in. 190 in2
6. Writing to Explain Tony says he does not have enough
information to find the area of this parallelogram. 7.2 cm
Is he correct? Explain.
14.5 cm
He is correct. He needs the height of the parallelogram to
calculate the area.
R 12•2 Copyright © Pearson Education, Inc., or its afﬁliates. All Rights Reserved. 6

2. Practice
12-2
Area of Parallelograms and
Find the area of each parallelogram or rhombus.
1. 2.
11 ft 9 cm
14 ft 12 cm
A 5 154 ft2 A 5 108 cm2
3. Rhombus 4. Parallelogram 5. Parallelogram
b 5 30 m b 5 18 in. b 5 20 ft
h 5 15.5 m h 5 2 _12 in. h 5 3 yd
A 5 465 m2 A 5 45 in2 A 5 180 ft2
6. Writing to Explain The area of a parallelogram is 42 square inches. The parallelogram’s
base is 6 inches. Find the height of the parallelogram. Explain how you do it.
Sample answer: I substituted the numbers I know into
the formula and solved for h. A 5 bh; 42 5 (6)h;
42 4 6 5 6h 4 6; 7 in. 5 h.
7. Number Sense A parallelogram has a base of 4 m and a height of
3 m. Find the area of the parallelogram in square centimeters.
(400)(300) 5 120,000 cm2
8. Estimation Which is the best estimate of the area of a parallelogram
that has a base of 11.42 cm and a height of 8.33 cm?
A 200 cm2 B 160 cm2 C 100 cm2 D 50 cm2
9. Reasoning The area of a figure is 36 cm2. Give 3 possible shapes of the figure.
Where possible give 3 possible sets of dimensions for each possible shape.
Square, rectangle, parallelogram; If the figure is a
square, the only possible dimensions are 6 cm 3 6 cm.
If the figure is a rectangle or a parallelogram,
possible dimensions are 3 cm 3 12 cm, 4 cm 3 9 cm,
1 cm 3 36 cm.
P 12•2 Copyright © Pearson Education, Inc., or its afﬁliates. All Rights Reserved. 6

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