Problema Solution
the length of a rectangle is 3cm less than twice its width. the area of the rectangle is 20 square cm. find the dimensions
Answer provided by our tutors
let
l = the length of the rectangle, l>0
w = the width of the rectangle, w>0
the length of a rectangle is 3cm shorter than twice the width
l = 2w - 3
the area of the rectangle is 20cm
l*w = 20
plug l = 2w - 3 in the above equation
(2w - 3)w = 20
by solving the quadratic equation
(2w - 3)w = 20
we find and consider the positive roots only since w>0
w = 4 cm
click here to see the step by step solution of the quadratic equation
l = 2w - 3 = 2*4 - 3 = 5 cm
the dimensions of the rectangle are 5 cm and 4 cm.