Answer: D
Explanation:
Since we are not given the height of the trapezoid, we can split this into a triangle and a rectangle. We find the area of each and then add them together. In order to do so, we must use Pythagorean Theorem to find the missing length so that we can find the area.
a²+b²=c²
a²+4²=8²
a²+16=64
a²=48
a=√48
a=4√3
Now that we know the missing length of the triangle, we can find the area of the triangle and the rectangle.
Triangle
A=1/2bh
A=1/2(4)(4√3)
A=8√3
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Rectangle
A=lw
A=7(4√3)
A=28√3
With our areas, we can add them together.
4√3+28√3=36√3 cm²