If a rectangle has a width of 42 inches and an area of 1638, how many rectangles of the same size would reach a length of 390 inches?
Let's think step by step below.
10
The rectangle has a length of 1638 in / 42in = 39 in.

The number of rectangles required to reach 390 inches is 390 / 39 = 10 rectangles.

.

So, the answer is 10