Problema Solution
The length of a rectangle is four times its width.
If the area of the rectangle is
400
cm2
, find its perimeter.
Answer provided by our tutors
Let
l = the length of the rectangle, l>0
w = the width of the rectangle, w>0
A = 400 cm^2 the area of the rectangle
P = 2(l + w) the perimeter of the rectangle
The length of a rectangle is 4 times its width:
l = 4w
The area of the rectangle A = l*w thus
l*w = 400
plug l = 4w into l*w = 400
4w*w = 400
........
click here to see the equation solved for w
........
w = 10 cm
l = 4*10
l = 40 cm
The perimeter P = 2(l + w):
P = 2(40 + 10)
P = 100 cm
The perimeter of the rectangle is 100 cm.