Question

the area of a trapezoid is 42 square feet and its height is 4 feet. the length of one base of the trapezoid is 9 feet. what is the lenght of its other base

Answer 1

Answer:

12

Step-by-step explanation:

area of a trapezoid :

$A = \frac{a+b}{2} h$

where a and b = length of bases and h = height

here, we are given the area, the length of one base and the height

we want to find the other base length

we can do this by plugging in what we are given and then solving for the unknown variable

first lets define our known variables

Area (A) = 42 , height (h) = 4 and length of one of the bases (a) = 9

we then plug this into the formula and solve for b, the other base length

recall formula : $A = \frac{a+b}{2} h$

A = 42 , h = 4 , a = 9

$42 = \frac{9+b}{2} 4$

now solve for b

divide both sides by 4

$10.5=\frac{9+b}{2}$

multiply both sides by 2

21 = 9 + b

subtract 9 from both sides

12 = b

the other base length is 12