The area of the rectangle is 42dm². What is the perimeter of the rectangle if its width is 6dm.

The opposite sides of a rectangle are equal, the area is calculated by the formula:
S = a * b.

Knowing its width, which is 6 dm and the area is 42 dm², we express the length (which corresponds to the quotient product and the second factor):

a = S: b = 42: 6 = 7 dm.

Let’s find the perimeter of such a figure by the formula:
P = 2a + 2b. Substitute the known values and write the expression:

P = 2 * 7 + 2 * 6 = 14 + 12 = 26 dm.