Answer:
a) 144π cm²
b) 248π cm²
Explanation:
Using the formula, curved surface area of a cone = πrl where r = radius and l = slant height,
Curved surface area of large cone = π (10) (12 + 3) = π (10)(15) = 150π
Curved surface area of small cone = π(2)(3) = 6π
a) Curved surface area of frustum = 150π - 6π = 144π cm²
b)
The frustum has a top surface which is a circle of radius 2 and a bottom surface which is also a circle of radius 10
The area of a circle is πr²
So Total area of both circles = π(2)² + π(10)² = 4π + 100π = 104π
Total surface area of frustrum = 144π + 104π = 248π cm²