Question

The length of a rectangle is 4 centimeters more than twice its width. If the perimeter of the rectangle is 86 centimeters , find the dimensions of the rectangle

Answer 1

P = perimeter = 2L + 2W = 86 cm.  Also, L = W + 4.  Subst. W + 4 for L, 

P = 2(W + 4) + 2W = 86 cm.  Then 2W + 8 + 2W = 86 cm, and 4W = 78 cm.

Finally solving for W, W = (78 cm)/4, or 19.5 cm.

If W = 19.5 cm, then L = W + 4 cm = 19.5 cm + 4 cm = 23.5 cm

The rectangle's dimensions are 19.5 cm by 23.5 cm.