To find the dimensions, create an equation for its perimeter and solve. Recall, the perimeter formula for a rectangle is P = 2l+2w. P is 34 cm. L is 4cm less than twice the width or 2w-4. And the width is w.
P = 2l+2w
34 = 2(2w-4) + 2w
34 = 4w -8 +2w
34 = 6w -8
34+8 = 6w
42 = 6w
7=w
The width is 7 cm. To find the length substitute w=7 into l=2w-4.
