The area of the rectangle is 32dm, its width is 40 cm, find the length of the rectangle and calculate its perimeter.

Since the opposite sides of the rectangle are equal, the area is calculated by the formula:
S = a * b. Provided that this value is 32 dm² and width = 40 cm = 4 dm (since 1 dm = 10 cm). Let us express the length:

a = S: b = 32: 4 = 8 dm.

The perimeter of such a figure is determined by the formula:
P = 2a + 2b. Substitute the dimensions of the rectangle and write the expression:
P = 2 * 4 + 2 * 8 = 8 + 16 = 24 dm.