SAT Question a490003a: Area and Volume answer and explanation with Desmos solution

Choice D is correct. It's given that the width of this rectangle is $7$ centimeters and that the length of this rectangle is $40$ centimeters longer than the width. Therefore, the length of this rectangle is $7+40$, or $47$, centimeters. The area of a rectangle can be found by multiplying its length and its width. Therefore the area, in square centimeters, of this rectangle is $\left(7\right)\left(47\right)$, or $329$.