Question

A cone has slanted height of 5cm and height of 4cm, its volume (in cm^3) is __________

(a) 38.71

(b) 36.50

(c) 37.00

(d) 37.71

I got this question in class test.

This intriguing question originated from Volume of a Right Circular Cone topic in division Surface Areas and Volumes of Mathematics – Class 9

Answer 1

Correct answer is (d) 37.71

The best explanation: From the figure shown below,

According to Pythagoras theorem, r^2 + h^2 = l^2

r = \(\sqrt{l^2-h^2}\)

= \(\sqrt{5^2-4^2}\)

= 3cm

We know that volume of a cone = \(\frac{1}{3}\) πr^2h

= \(\frac{1}{3} * \frac{22}{7}\) * 3 * 3 * 4

= 37.71.