SOLUTION: Given a rectangle whose length is always 5 times of its width. Express the area A of this rectangle in a function of its perimeter . Step1: Assume that the length and width of

Algebra ->  Volume -> SOLUTION: Given a rectangle whose length is always 5 times of its width. Express the area A of this rectangle in a function of its perimeter . Step1: Assume that the length and width of       Log On


   



Question 121887: Given a rectangle whose length is always 5 times of its width. Express the area A of this rectangle in a function of its perimeter .
Step1: Assume that the length and width of the rectangle are L and W respectively. Then can be expressed in terms of , i.e. Express L and W as functions of X:

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!
The perimeter of a rectangle is given by P=2L+%2B+2W, but we are given that the dimensions of this rectangle always have the relationship L=5W, so let's use that information to express the perimeter in terms of just W:

P=2%285W%29%2B2W
P=10W%2B2W
P=12W

But now we can express the width, W, in terms of P by dividing by 12:

W=P%2F12

The area of a rectangle is given by A=LW, but we still know that L=5W, so the area of this rectangle is A=5W%2AW or A=5W%5E2

But we have developed an expression for W in terms of the perimeter, P, so let's substitute that for W in the area equation:

A=5%28P%2F12%29%5E2, or

A=5P%5E2%2F144