A) Find the dimensions of the rectangle with area 324 square inches that has minimum perimeter, and then find the minimum perimeter.

Question

L=_____, W=18, Minimum Perimeter= 72

Answer 1

A = L*w

324 = L*w

324/w = L

P = 2*( L + w)

= 2 * ( 324/w + w)

= 648/w + 2w

= (648 + 2w^2)/w

without calculus, the minimum must be found numerically, by examining the graph.

The minimum does occur at w=18. Length then must also be 18.

Min perimeter is therefore 72