Kira has feet of fencing. She will use it to form three sides of a rectangular garden. The fourth side will be along a house and will not need fencing. For the area of the garden to be the maximum, how long should the side opposite the house be?
4 answers
You failed to indicate how many feet of fencing Kira has.
let the perimeter be P, where P is a constant
let the length be y and the width be x
2x + y = P
y = P - 2x
Area = xy
= x(P-2x) - Px - 2x^2
d(area)/dx = P - 4x
= 0 for a maximum area
4x = P
x = P/4
y = P - P/2 = P/2
So the long side should be half the perimeter, and the short side whould be a quarter of the perimeter.
let the length be y and the width be x
2x + y = P
y = P - 2x
Area = xy
= x(P-2x) - Px - 2x^2
d(area)/dx = P - 4x
= 0 for a maximum area
4x = P
x = P/4
y = P - P/2 = P/2
So the long side should be half the perimeter, and the short side whould be a quarter of the perimeter.
i need help with my math homework
if the perimeter of a rectangle is 184cm and the width is 39cm calculate its length