The radii of the ends of a frustum of a cone 7 cm high are 5 cm and 3 cm. Find its volume correct to one decimal place. (Use $\pi=\frac{22}{7}$ )
Answer & explanation
Correct answer: option 2
Volume of a frustum of cone = \(\frac{π}{3}\)h(R2 + r2 + Rr)
= \(\frac{22}{7}\) × \(\frac{7}{3}\) × (52 + 32 + 5 × 3)
= \(\frac{22}{7}\) × 49 = 359.3 cm3