Answer:
C. 21 in² . . . . your answer selection is correct.
Step-by-step explanation:
The area of a triangle is given by the formula ...
A = 1/2bh
where b represents the base of the triangle, and h represents the height of the opposite vertex above that base.
The figure shows you that half the base is 3 in and the height is 7 in, so the area is ...
A = (1/2b)h = (3 in)(7 in) = 21 in² . . . . matches choice C
