Hey, need some help with the steps needed to solve these problems.

1) calculate the total surface area (inside and outside and both ends) of a gas pipe. length 3.5m, outside diameter 55mm, inside diameter 50mm.

2) determine the volume of metal used in the making of the gas pipe.

3) a) determine the number of complete revolutions a motorcycle wheel will make in traveling 5km if the wheel's diameter is 80.2cm.

b) water flows in a 1000mm diameter pipe to a depth of 800mm calculate:

i) the wet perimeter of the pipe.

ii) the area of cross section of the water.

thanks.