Explanation:
oh, come on. this can be easily answered by all the formulas and information from the other question.
again the area of a circle is
pi×r²
so, for the given area of 9pi this means the radius is
r = sqrt(9) = 3 cm
the slant height is 4 times the radius
L = 3×4 = 12 cm
the total surface area of a cone is again
pi×r(r + L) = pi×r² + pi×r×L
the lateral area alone (without the base area) is then
pi×r² + pi×r×L - pi×r² = pi×r×L
in our case
3.14×3×12 = 113.04 ≈ 113 cm²