The diameter of the base of a right circular cone is 10 cm and its height is 12 cm. What is the total surface area (in cm2) of the cone?
Answer & explanation
Correct answer: option 1
We know that,
Total surface area of right circular cone = πr(l + r)
l2 = h2 + r2
We have,
The diameter of the base of a right circular cone = 10 cm
So, Radius of the cone = 5 cm
Height of the cone = (h) = 12 cm
According to the question,
l2 = 52 + 122
= l2 = 25 + 144 = 169
= l = 13 cm
Total surface area of the cone = π × 5(13 + 5) = π × 5 × 18 = 90π cm2