Lesson Vocabulary

• height of a trapezoid

Take note Theorem 10-4: Area of a Trapezoid

The area of a trapezoid is half the product of the height and the sum of the bases.

A = 1 2 h ( b 1 + b 2 ) eh equals . 1 half , h . open , b sub 1 , plus , b sub 2 , close

Problem 1 Area of a Trapezoid

Geography What is the approximate area of Nevada?

A = 1 2 h ( b 1 + b 2 ) Use the formula for area of a trapezoid .   = 1 2 ( 309 ) ( 205 + 511 ) Substitute  309  for  h ,   205  for  b 1 ,  and  511  for  b 2 .   = 110 , 622 Simplify . table with 3 rows and 3 columns , row1 column 1 , eh , column 2 equals , 1 half , h open , b sub 1 , plus , b sub 2 , close , column 3 cap usetheformulaforareaofatrapezoid . . , row2 column 1 , , column 2 equals , 1 half . open 309 close . open . 205 plus 511 . close , column 3 cap substitute . 309 , for , h comma 205 , for , b sub 1 , comma , and , 511 , for , b sub 2 , . , row3 column 1 , , column 2 equals 110 comma 622 , column 3 cap simplify , . , end table

The area of Nevada is about 110 , 600   mi 2 . 110 comma 600 , mi squared , .

✓ Got It?

1. What is the area of a trapezoid with height 7 cm and bases 12 cm and 15 cm?