True or False: (x + 3)2 = x2 + 9
1 answer:
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Answer:
(d) 80 square units
Step-by-step explanation:
As with many composite area problems, this can be worked any of several ways. The attached shows trapezoid ABCE, from which triangle CDE can be removed to get the desired area.
The relevant formulas are ...
A = (1/2)(b1 +b2)h . . . . . . area of a trapezoid
A= (1/2)bh . . . . . . . . . . . . area of a triangle
__
Here, the trapezoid has bases 12 and 2, and height 12, so its area is ...
A = (1/2)(12 +2)(12) = 84 . . . . square units
The triangle has a base of 4 and a height of 2, so its area is ...
A = (1/2)(4)(2) = 4 . . . . square units
Then the area of the desired figure is ...
84 - 4 = 80 . . . . square units
