Question 433993
Unless it is specifically mentioned that it is lateral surface area, the surface area mentioned is TOTAL, and so

{{{SA = 2pi*r^2 + Ch = 2pi*(d/2)^2 + (pi*d)*d = 2pi*(d^2/4) + pi*d^2

= pi*(d^2/2) + pi*d^2 = (3pi*d^2)/2


}}}
Hence {{{(3pi*d^2)/2 = 200}}}==> {{{d^2 = 400/(3pi)}}}
==> {{{d = 200/sqrt(3pi)}}} cm
==> {{{r = 100/sqrt(3pi)}}} cm.