The formula V=πr2h can be used to find the volume of a cylinder, where h is the height of the cylinder and r is the radius of the cylinder. A hockey puck is in the shape of a cylinder with a height of 25 millimeters and a radius of 38 millimeters. Which is the approximate volume of the hockey puck?

The coverage of a base station of a telecommunication company forms a disk with a radius of (kilometers). let be the distance of a cellphone from a base station. assume that the location of cellphones in use are randomly uniformly distributed within the disk. calculate the mean and variance for the random variable.