Answer:
12 cm
Step-by-step explanation:
The total surface area of the cone = area of base + area of curved surface
Subtract the base area from total area, that is
πrs = area - πr²
r is the radius and s the slant height
πrs = 417.8 - (π × 7²) = 263.86
Divide both sides by πr
s = [tex]\frac{263.86}{7\pi }[/tex] ≈ 12 cm
