3. Example Problems III

A corn cob (see Fig.), shaped somewhat like a cone, has the radius of its broadest end as \(2.1 cm\) and length (height) as \(20 cm\). If each \(1 cm^2\) of the surface of the cob carries an average of four grains, find how many grains you would find on the entire cob.

 

 

Number of grains \(=\)