geometry
posted by peter on .
The rectangle ABCD is rotated about the side AB. Find the volume of the solid defined by this rotation.
AB = DC = 4cm
AD = CB = 2cm

The real problem is that I do not comprehend the question.
The part I'm really stumbling over is the "rotated about the side AB". I have no idea what that means..
I have another question that is quite similar...so if anyone can explain, it would be greatly appreciated. 
What you get when you perform the indicated rotation of the rectangle about side AB is a cylinder with radius = 2 cm and length h = 4 cm. The line AB is the axis of the cylinder.
The volume is
V = pi*r^2*h = 16*pi cm^3
Do the calculation. 
I've got it!
Thank you very much for your help!