need this ASAP:
a rectangular enclosure must have an area of at least 800yd^2. If 180yd of fencing is to be used, and the width cannot exceed the length, withing what limits must the width of the enclosure be?

Question

need this ASAP:
a rectangular enclosure must have an area of at least 800yd^2. If 180yd of fencing is to be used, and the width cannot exceed the length, withing what limits must the width of the enclosure be?

anonymous · Answer

wait so what am i doing?
sorry i dont have much time

xishem · Answer

Since the area is 800yd^2 or greater...$$(l*w)>=A_{\min}$$And...$$2l+2w=length_{fence}$$...$$2l+2w=180 \rightarrow l=\frac{180-2w}{2} \rightarrow l=90-w$$Substitute back into the area equation, including the explicit value for the minimum area...$$l*w >= A_{\min} \rightarrow (90-w)*w>=800$$$$90w-w^2 >= 800 \rightarrow w^2-90w+800 >= 0$$I'm not going to take you any further than that. You'll have to work it out on your own. Try it and see how far you can get.

xishem · Answer

Sorry, it should be...$$w^2-90w+800 <= 0$$

anonymous · Answer

10<=x<=80.......?

anonymous · Answer

@Xishem ?

jim_thompson5910 · Answer

you're close, but keep in mind that "the width cannot exceed the length"

So  $\Large W \le L$