Question

A trapezoid has an area of 60 square feet. If the trapezoid has a base measuring 4 feet and a height of 12 feet, what is the length of the other base?

A. 4 ft
B. 6 ft
C. 10. ft
D. 12 ft

Answer 1

Let a = given base

Let b = the other base

Let h = height

A = (1/2)(a + b)h

60 = (1/2)(4 + b)(12)

We now solve for b.

60 = 6(4 + b)

60 = 24 + 6b

60 - 24 = 6b

36 = 6b

36/6 = b

6 = b

The other base measures 6 feet.

Answer 2

B

Explanation:

the area of a trapezoid (A) is calculated using the formula

A =
`(1)/(2)` h(a + b)

where h is the height and a, b the parallel sides

here h = 12, a = 4 and A = 60, hence

`(1)/(2)` × 12(4 + b) = 60

6(4 + b) = 60 ( divide both sides by 6 )

4 + b = 10 ( subtract 4 from both sides )

b = 6

Hence the other base = 6 ft → B