Explanation:
the area is
baseline × height.
remember, 2 lengths are multiplied.
since both figures are similar to each other, it means that both lengths are changed by the same scaling factor.
18 × f = 63
f = 63/18 = 7/2
this factor f applies (as mentioned) to the baseline AND to the height.
therefore, the area changes by f×f = f² = 49/4.
that means the area of the larger figure is
216 × 49/4 = 54 × 49 = 2,646 yd²