Answer:
225 m²
Step-by-step explanation:
If W is the width of the rectangle, and L is the length, then:
60 = 2W + 2L
A = WL
Use the first equation to solve for one of the variables:
30 = W + L
L = 30 − W
Substitute into the second equation:
A = W (30 − W)
A = 30W − W²
This is a parabola, so we can find the vertex using the formula x = -b/(2a).
W = -30 / (2 × -1)
W = 15
Or, we can use calculus:
dA/dW = 30 − 2W
0 = 30 − 2W
W = 15
Solving for L:
L = 30 − W
L = 15
So the maximum area is:
A = WL
A = (15)(15)
A = 225
