SOLUTION: The length of a rectangular field is 30m greater than its width, w metres. i) Write down an expression for the area A m^2 of the field, in terms of w. I got this to be w(w+30)

Algebra ->  Rectangles -> SOLUTION: The length of a rectangular field is 30m greater than its width, w metres. i) Write down an expression for the area A m^2 of the field, in terms of w. I got this to be w(w+30)       Log On


   

Question 498880: The length of a rectangular field is 30m greater than its width, w metres.
i) Write down an expression for the area A m^2 of the field, in terms of w.
I got this to be w(w+30)
ii) The area of the field is 8800m^2. Find its width and perimeter.
This is where I'm stuck. I know the perimeter is 2 x the width + 2 x the length but I have no idea how to work out the width from that. Many thanks.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The length of a rectangular field is 30m greater than its width, w metres.
:
i) Write down an expression for the area A m^2 of the field, in terms of w.
I got this to be w(w+30)
;
ii) The area of the field is 8800m^2. Find its width
w(w+30) = 8800
w^2 + 30w - 8800 = 0; a quadratic equation
you can solve this with the quadratic formula, but it will factor to
(w-80)(w+110)
positive solution
w = 80 meters is the width
then
80 + 30 = 110 meters is the length
:
and perimeter. Sounds like you know how to do this now