Math probloms i dont understand

Question

The area of a rectangle with whole-number dimensions is 42 square meters. The least possible perimeter of the rectangle is meters.

Answer 1

You can solve this by asking and solving two important questions:

1. What are all the possible rectangles with area equal to 42?
2. Of these rectangles, which of these has the smallest perimeter?

Answer 2

The least possible perimeter of the rectangle is the smallest possible perimeter..

Given we have the area of rectangle = 42 sq. m

Letting a be the length and b be the width of rectangle,

we have,

Area = 42 = ab

Perimeter = P = 2(a+ b) = 2a + 2b

Squares are the rectangles of smallest perimeter. Thus,

a^2=42

a= -6.48 and 6.48

Since a is length so we take positive a, a=6.48

thus, b=6.48

gives perimeter 25.9 = 26m

Notice a = 6.48 , b = 6.48 is a square.