Question 859356
Find the dimensions of the rectangle with maximum area whose perimeter is 120ft.
let y=length of rectangle
let x=width of rectangle
2x+2y=120
x+y=60
y=60-x
...
Area=length*width=x*y=x(60-x)*y=60x-x^2
Area=-x^2+60x
complete the square:
Area=-(x^2-60x+900)+900
Area=-(x-30)^2+900
x=30
y=60-x=30
Dimensions of rectangle with maximum area whose perimeter is 120ft. 30 ft by 30 ft