Answer:
Length = 225 ft
Width = 150 ft
Step-by-step explanation:
If L is the length and W is the width, then:
900 = 2L + 3W
A = LW
Solve for W in the first equation:
3W = 900 − 2L
W = 300 − ⅔ L
Substitute into the area equation:
A = L (300 − ⅔ L)
A = 300L − ⅔ L²
Use calculus to find dA/dL and set to 0, or use the formula for vertex of a parabola.
Using calculus:
dA/dL = 300 − 4/3 L
0 = 300 − 4/3 L
L = 225
Using vertex formula:
L = -b / (2a)
L = -300 / (-4/3)
L = 225
Find the width:
W = 300 − ⅔ L
W = 150
You got the right answers, but the problem says to assume that the length is greater than the width.
