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Q7: A farmer wants to build a metal fence to enclose his livestock. The fence's vertices are represented by

points A(4,-4), B(-4,-4), C(-4, 3), D(1, 3), E(1,-1), and F(4,-1). Each unit in the coordinate plane
represents 1 meter in reality. Since a gate is to be added between points A and F. the farmer will not use
metal fencing on that side. What is the total number of meters of metal fencing the farmer needs?

asked
User Kozue
by
7.6k points

1 Answer

7 votes

Answer:down below

Step-by-step explanation:A square gives the greatest area. If the river were not there, you would divide 1700 by 4 to get a square 425 feet by 425 feet. Because of the river, add 425 feet to the side opposite the river to get a rectangle 425 feet by 850 feet.

Now for the algebra that you need.

P=2l+2w but there is only one length.

P=l+2w

1700=l+2w

1700-2w=l

A=lw

A=(1700-2w)w

A=1700w-2w2

This is a parabola that opens downward so there is a maximum point, the vertex, which is (h,k).

h=-b/2a is the "maximizing point" and k is the maximum area

-b/2a=-1700/(-4)

-b/2a=425 feet

One width will be 425 feet, the length will be (425+425)=850 feet, and the second width will also be 425 feet.

A=lw

The maximum area will be A=850*425=361,250 square feet.

Notice that if you substitute 425 into the equation A=1700w-2w2 you will get the same answer.

1700*425-2*4252

722,500-2*180,625

722,500-361,250

answered
User Adeel Shekhani
by
7.5k points
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