Volumes of Pyramids and Cones: Please help!

Algebraically prove that a clockwise and counterclockwise rotation of 180° about the origin for triangle abc are equivalent rotations.

Gables properties corp. is leasing office building with an area of 49b^2+70b+25. what is the shape of the building? a) rectangle b) square

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.