Problem 1 Finding the Area of a Parallelogram

What is the area of each parallelogram?

You are given each height. Choose the corresponding side to use as the base.

A = b h   A = b h   = 5 ( 4 ) = 20 Substitute for  b  and  h .   = 2 ( 3.5 ) = 7   The area is  20  in . 2 .     The area is  7 cm 2 . table with 3 rows and 5 columns , row1 column 1 , eh , column 2 equals b h , column 3 , column 4 eh , column 5 equals b h , row2 column 1 , , column 2 equals 5 , open 4 close , equals 20 , column 3 cap substitutefor . b , and , h . , column 4 , column 5 equals 2 , open 3.5 close , equals 7 , row3 column 1 , , column 2 cap theareais . 20 , in , . squared , . , column 3 , column 4 , column 5 cap theareais . 7 , cm squared , . , end table

✓ Got It?

1. What is the area of a parallelogram with base length 12 m and height 9 m?

Problem 2 Finding a Missing Dimension

For ▱ A B C D , white parallelogram eh b c d comma  what is DE to the nearest tenth?

First, find the area of ▱ A B C D . white parallelogram eh b c d .  Then use the area formula a second time to find DE.

A = b h   = 13 ( 9 ) = 117  Use base  A D  and height  C F . table with 2 rows and 2 columns , row1 column 1 , eh , column 2 equals b h , row2 column 1 , , column 2 equals 13 , open 9 close , equals 117 . cap usebase eh d . andheight c f . , end table

The area of ▱ A B C D white parallelogram eh b c d  is 117  in . 2 . 117 , in , . squared , .

A = b h 117 = 9.4 ( D E ) Use base  A B  and height  D E . D E = 117 9.4 ≈ 12.4 table with 3 rows and 2 columns , row1 column 1 , eh , column 2 equals b h , row2 column 1 , 117 , column 2 equals 9.4 open d e close . cap use base eh b . and height d e . , row3 column 1 , d e , column 2 equals , 117 over 9.4 , almost equal to , 12.4 , end table

DE is about 12.4 in.

✓ Got It?

2. A parallelogram has sides 15 cm and 18 cm. The height corresponding to a 15-cm base is 9 cm. What is the height corresponding to an 18-cm base?