Question

The radius (in cm) of the largest right circular cone that can be cut out from a cube of edge $4.2$ cm is:

• A. $4.2$
• B. $2.1$
• C. $8.4$
• D. $1.05$

Answer 1

The correct option is B $2.1$

The base of largest cone that can be cut out from a cube touches all the edges of the base of the cube and its height is same on the edge of the cube.

Edge of the cube $=4.2cm$

$\therefore 2r=4.2cm\Rightarrow r=2.1cm$

Therefore radius of the largest circular cone that can be cut out from the cube of edge $4.2cm$ is $2.1cm$.