# Thread: Finding a rule, domain and area.

1. ## Finding a rule, domain and area.

The dimensions of an enclosure are shown. The perimeter of the enclosure is 160m.
a) Find a rule for the area, A m^2, of the enclosure in terms of x.
b) State a suitable domain of the function A(x).
c) Find the maximum possible area of the enclosure and state the corresponding values of x and y.

2. I don't see a picture...

3. I thought I did post the picture. But I can't get it to work.
No worries. Thanks for letting me know it doesn't show up.

4. Originally Posted by grooverandshaker
The dimensions of an enclosure are shown. The perimeter of the enclosure is 160m.
a) Find a rule for the area, A m^2, of the enclosure in terms of x.
b) State a suitable domain of the function A(x).
c) Find the maximum possible area of the enclosure and state the corresponding values of x and y.
Without the picture I guess that:

(a) A = xy ... (1)

But 2x + 2y = 160 => y = 80 - x .... (2)

Substitute equation (2) into (1):

A = x(80 - x).

The remaining questions are left for you to do. If you need more help, please show all your qork and say where you get stuck.

Note to potential posters: Since this question has been posted in the PRE-calculus subforum, calculus is not permitted.