Q.4 (3) The radii of the circular ends of a frustum of a cone are 14 cm and 8 cm. If the height of the frustum is 8 cm, find : (π = 3.14)(i) Curved surface area of frustum.(ii) Total surface area of the frustum.(iii) Volume of the frustum.

Answer: (i) 690.8 cm²; (ii) 1507.2 cm²; (iii) 3114.88 cm³

r₁ = 14, r₂ = 8, h = 8. Slant height \(l = \sqrt{h^2 + (r_1 - r_2)^2} = \sqrt{64 + 36} = 10\) cm.

(i) CSA = \(\pi l (r_1 + r_2)\) = 3.14 × 10 × 22 = 690.8 cm².

(ii) TSA = CSA + \(\pi r_1^2 + \pi r_2^2\) = 690.8 + 3.14 × (196 + 64) = 690.8 + 816.4 = 1507.2 cm².

(iii) V = \(\tfrac13 \pi h (r_1^2 + r_2^2 + r_1 r_2)\) = \(\tfrac13\) × 3.14 × 8 × (196 + 64 + 112) = \(\tfrac13\) × 3.14 × 8 × 372 = 3.14 × 8 × 124 = 3114.88 cm³.