4. The altitude of a right circular cone is 15 and the radius of its base is 8. A cylindrical hole of diameter 4 is drilled through the cone, with its axis along the axis of the cone, leaving a solid. What is the volume of this solid?

Respuesta :

Given:

The altitude of a right circular cone = 15

The radius of the base = 8

A cylindrical hole of diameter 4 is drilled through the cone, with its axis along the axis of the cone.

So, the radius of the cylinder = 2

We will find the height of the cylinder using the ratio and proportional

Let the height of the cylinder = h

so,

[tex]\begin{gathered} \frac{h}{15}=\frac{6}{8} \\ \\ h=\frac{6\cdot15}{8}=11.25 \end{gathered}[/tex]

So, the height of the cylinder = 11.25

The volume of the solid = the volume of the cone - the volume of the cylinder

The volume of the cone =

[tex]\frac{1}{3}\pi\cdot r^2h=\frac{1}{3}\cdot3.14\cdot8^2\cdot15=1004.8[/tex]

The volume of the cylinder =

[tex]\pi\cdot r^2\cdot h=3.14\cdot2^2\cdot11.25=141.3[/tex]

So, the volume of the solid =

[tex]1004.8-141.3=863.5[/tex]

so, the answer will be: Volume of the solid = 863.5