Answer:
400 m^2.
Step-by-step explanation:
The largest area is obtained where the enclosure is a square.
I think that's the right answer because a square is a special form of a rectangle.
So the square would be 20 * 20 = 400 m^2.
Proof:
Let the sides of the rectangle be x and y m long
The area A = xy.
Also the perimeter 2x + 2y = 80
x + y = 40
y = 40 - x.
So substituting for y in A = xy:-
A = x(40 - x)
A = 40x - x^2
For maximum value of A we find the derivative and equate it to 0:
derivative A' = 40 - 2x = 0
2x = 40
x = 20.
So y = 40 - x
= 40 - 20
=20
x and y are the same value so x = y.
Therefore for maximum area the rectangle is a square.
Answer:
Step-by-step explanation:
Let h bet the height of the building.
Mark is 60+310 = 370 m from building.
35/60 = h/370
h = 1295/6 = 215⅚ meters
Triangle ABC and triangle DCE are congruent, so line DE = line AB
Use the cosine rule to find angle ACB
Angle ACB = 48.1°
You have to show the question more I can’t see the graph
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