Question

In the adjoining figure, the slant height of the conical part is:

Options

• 4 cm

• 7 cm

• 5 cm

• 25 cm

Answer 1

5 cm

Explanation:

In the vertical cross-section, the slant height is the hypotenuse of a right triangle whose vertical height is 4 cm and base radius is 3 cm.

By Pythagoras `l = sqrt(4^2 + 3^2)`

= `sqrt(16 + 9)`

= 5 cm 

This is the same method used for a cone surmounted on a hemisphere.