What is the maximum area for a rectangle with a perimeter of 130 meters?

Question

What is the maximum area for a rectangle with a perimeter of 130 meters

Answer 1

Perimeter of  rectangle with sides a and b p=2(a+b)=130

a+b=75,  b=75-a

Area: S=a*b=a(75-a)

To find maximum area we have to maximize a*(75-a), which would reached for x=75/2, and the area would be  5625/4. I think you know to find maximum of quadratic  function.