It decreased by twenty five precent 25%
Answer:
- 12 ft parallel to the river
- 6 ft perpendicular to the river
Step-by-step explanation:
The least fence is used when half the total fence is parallel to the river. That is, the shape of the rectangle is twice as long as it is wide.
72 = W(2W)
36 = W²
6 = W . . . . . . the width perpendicular to the river
12 = 2W . . . . the length parallel to the river
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<em>Development of this relation</em>
Let T represent the total length of the fence for some area A. Then if x is the length along the river, the width is y=(T-x)/2, and the area is ...
A = xy = x(T -x)/2
Note that the equation for area is that of a parabola with zeros at x=0 and at x=T. That is, for some fence length T, the area will be a maximum at the vertex of this parabola. That vertex is located halfway between the zeros, at ...
x = (0 +T)/2 = T/2
The corresponding area width (y) is ...
y = (T -T/2)/2 = T/4
Equivalently, the fence length T will be a minimum for some area A when x=T/2 and y=T/4. This is the result we used above.
The slope would have to be -3
Answer:
The total length is 1123 feet.
a) if the model is 30 inches long, the first thing we need to do is write inches in feets, so 1 feet is equivalent to 12 inches.
so 30 inches are 30/12 = 2.5 feets.
the scale is the ratio between the feets in the the two lengths.
1123/2.5 = 449.2
so the scale is 1:449.2
so each feet in the model is equivalent to 449.2 feets in the enterprise.
b) if the model is 2 feet long, then:
1123/2 = 561.5
the scale is 1:561.5
so each feet in the model is equivalent to 561.5 feets in the enterprise.
