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?

90 π

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