the formula of cone's capacity is V = (1 / 3) (pi x r x h)
we know that r = 3.5, we must find h, the slant height is H=6.5, applying pythagorean theorem h ^2 = H^2, so h= sqrt (H^2 - r^2)
h = sqrt (6.5^2 - 3.5^2) = 5.47
finally, V = (1 / 3) (3.14 x 3.5 x 5.47) = 20.03 cm^3
the surface are is A = pi x r x H = 71.43 cm^2
