Length of the wire l = 2h + 2r + πr.
From the above equation, find the expression for h.
The area of frame L = h*2r + 1/2*π*r^2.
Substitute for h and find L.
For maximum area, find dL/dr and equate it to zero. Hence find r.
In the problem length of the wire l = 60 cm is given. Substitute this value in the first equation, rearrange the terms so that the equation should be
h = .............?