Let “x” be the width. Then the length would be 6x (6 times the width “x”). We know the perimeter is the sum of all the sides of a shape, and since a rectangle has two pairs of equal sides (x and x; 6x and 6x) then all we need to do is add all the sides and isolate x.
P = 2 width + 2 length 42 = 2*x + 2*6x 42 = 2x + 12x 42 = 14x x = 42/14 x = 3
So the width is 3 units and the length is 6*3 units, or 18 units.
