3. Five marks example problems - II

1. The internal and external radii of a hollow hemispherical shell are 3 \(cm\) and 5 \(cm\), respectively. Find the C.S.A. and T.S.A. of the shell.

 

Answer:

 

The curved surface area of the shell \(=\)  \(cm^2\)

 

The total surface area of the shell \(=\)  \(cm^2\)

 

[Note: Enter your answer up to two decimal places]

 

 

2. A sphere, a cylinder and a cone are of the same radius, where as cone and cylinder are of same height. Find the ratio of their curved surface areas.

 

 

Answer:

 

The ratio of their curved surface areas \(=\) $i\sqrt{i}:\sqrt{i}:i$

 

 

3. An industrial metallic bucket is in the shape of the frustum of a right circular cone whose top and bottom diameters are \(10 \ m\) and \(4 \ m\) and whose height is \(4 \ m\). Find the curved and total surface area of the bucket.

 

Answer:

 

Curved surface area \(=\)  \(m^2\)

 

Total surface area \(=\)  \(m^2\)

 

[Note: Enter your answer up to two decimal places]