Express the perimeter as a function of width? please help

[jillpil87]

For a rectangle whose area is 50 square inches, express the perimeter as a function of the width.

I have no idea...

 

[daon]

You know:

A = l*w

So, 50 = l*w, or, solving for l: l=50/w.

You also know:

P = 2l + 2w. With the above Area manipulation, you have l=50/w. Substitute this into the perimiter equation:

P = 2l + 2w --> P = 2(50/w) + 2w --> P = 100/w + 2w

Now P is a function of the width of the rectangle!

 

[jillpil87]

thanks

thanks so much, I was in the right direction I just needed that extra little push.