Ally is making a scale diagram of her classroom. she uses a scale factor of 3 centimeters per foot to draw the diagram. the actual length of the classroom is 18 feet, and its width is 20 feet. what is the area of the scale drawing of the classroom?

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.