Answer: 132 square units
Step-by-step explanation:
Area of a trapezoid:
a = top base; b = bottom base; h = height
[tex]A=\frac{a+b}{2}+h[/tex]
Find the bases and the height:
b: 21 (given)
h: 8 (given)
a: find from the bottom
need to find the only not given value by subtracting the values we know. (this might be a little confusing but I think it'll be easier if you look at the original picture)
21 - 9 - 3 = 9
add the new number with the given length of the top base
9 + 3 = 12
Substitute the values into the equation:
[tex]A=\frac{a+b}{2}+h\\[/tex]
[tex]A=\frac{12+21}{2}+8[/tex]
(I used a calculator to find it out)
Area = 132 square units
