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.

Correct option is B

Given:
Radius of the larger base (R) = 5 cm
Radius of the smaller base (r) = 3 cm
Height (h) = 7 cm
Formula Used:
Volume of a frustum of a cone = $$\frac{1}{3} \pi h (R^2 + r^2 + R \cdot r) \\$$​​
Solution:
​$$\text{Volume} = \frac{1}{3} \pi \times 7 (5^2 + 3^2 + 5\times 3) \\\ \\\text{Volume} = \frac{1}{3} \pi \times 7 (25 + 9 + 15) \\\ \\\text{Volume} = \frac{1}{3} \pi \times 7\times 49 \\\ \\\text{Volume} = \frac{343}{3} \pi \\\ \\\text{Volume} \approx 359.3 \, \text{cm}^3$$​​