Answer:
64 × pi m²
Step-by-step explanation:
the formulas needed for the surface area of a cone are :
base area plus the "mantle", the lateral "wall" around it.
the base area is a circle.
so, that formula is Ac = pi×r²
the "wall" formula is Aw = pi×r×s
r = radius
s = slant height = 12
the formula for the surface area of a sphere is
As = 4×pi×r²
we know now, that both surface areas are the same, and also the radius is the same for both objects.
Ac + Aw = As
pi×r² + 12×pi×r = 4×pi×r²
=>
12×pi×r = 3×pi×r²
12×pi = 3×pi×r
12 = 3×r
r = 4 m
now, we only need to use this value of r in our formulas for surface areas, like for the sphere :
4×pi×r² = 4×pi×4² = 4³×pi = 64×pi
