The formula for the volume of the cylindrical pipe is :

1. π(R + r) h

2. π(R — r)h

3. π(R² + r²) h

4. π(R² - r²) h

A rectangular piece of paper 10 cm by 8 cm is rolled along its width to get the cylinder of largest size. The curved surface area of the cylinder formed is :

1. 44 cm²

2. 20 cm²

3. 80 cm²

4. 80 cm²

The ratio between the curved surface area and the total surface area of a cylinder is 1 : 2. Find the ratio between the height and the radius of the cylinder.

The total surface area of a cylinder is 6512 cm² and the circumference of its base is 88 cm. Find :

(i) its radius

(ii) its volume