Respuesta :
Answer:
Because it is a rectangle, the area is expressed as A = xy, or length times width.
Because it is next to the river, he only needs to fence three sides, so F = x + 2y.
Knowing the amount of fencing available is 7500m, we get:
7500 = x + 2y solve for x
x = 7500 - 2y substitute into the area equation
A = (7500 - 2y)y distribute
A = -2y2 +7500y
You can see that this is a parabola which opens down, meaning that the point of maximum area will be at the vertex, y = -b/2a = -7500/[2(-2)] = 1875
x = 7500 - 2(1875) = 3750
A = 3750(1875) = 7,031,250 m2
Step-by-step explanation:
The largest area that can be enclosed is 781250 m²
Area of rectangle
- area = lw
where
l = length
w = width
The farmer wants to enclose a rectangular plot that borders a river. He is not fencing the side along the river. Therefore,
perimeter = l + 2w
l = 2500 - 2w
Therefore,
area = (2500 - 2w)w
(2500 - 2w)w = 0
w = 0 or 1250
average = 1250 / 2 = 625 meters
Hence, the max area is at w = 625 meters
Therefore,
l = 2500 - 2(625) = 1250
length = 1250 meters
width = 625 meter
Therefore,
area = 1250 × 625 = 781250 m²
Therefore, the largest area that can be enclosed is 781250 m²
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