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 this forum we will give the hint. If you want to learn the subject you have to the calculations yourself.
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 = .............?