The volume of a cone is 462 cm3. Its base radius is 7 cm then its hei

1.	The volume of a cone is 462 cm3. Its base radius is 7 cm then its height is ………… cm.A) 10.3 B) 7 C) 8 D) 9
Answer» Correct option is: D) 9 Given that radius of base of the cone is r = 7 cm. Let h be the height of the cone. Then volume of the cone = \(\frac 13 \pi r^2h\) \(\therefore\) \(\frac 13 \pi r^2h\) = 462 \(\Rightarrow\) h = \(\frac {462 \times 3 \times 7}{22 \times 7 \times 7}\) (\(\because\) r = 7 cm) = \(\frac {21\times 3}{7} = 3\times 3 = 9 \, cm\) Hence, height of the cone is 9 cm Correct option is: D) 9

The volume of a cone is 462 cm3. Its base radius is 7 cm then its height is ………… cm.A) 10.3 B) 7 C) 8 D) 9

Answer»

Correct option is: D) 9

Given that radius of base of the cone is r = 7 cm.

Let h be the height of the cone.

Then volume of the cone = \(\frac 13 \pi r^2h\)

\(\therefore\) \(\frac 13 \pi r^2h\) = 462

\(\Rightarrow\) h = \(\frac {462 \times 3 \times 7}{22 \times 7 \times 7}\) (\(\because\) r = 7 cm)

= \(\frac {21\times 3}{7} = 3\times 3 = 9 \, cm\)

Hence, height of the cone is 9 cm

Correct option is: D) 9