Please help surface area of triangular pyramid

Events a and b are independent. the probability of a occurring is 2/5. the probability of b occurring is 1/4. what is p(a and b)?

Agrid shows the positions of a subway stop and your house. the subway stop is located at (-5,2) and your house is located at (-9,9). what is the distance, to the nearest unit, between your house and the subway stop?

The water aquarium shark tank is always greater than 25 feet of the water level decreased by 6 feet during cleaning what was the water level before the cleaners took out any water