What must the values of a and b be for PQRS (below) to be a parallelogram? plz helppp asap

The multiplication property of zero states that the product of any number and 0 is 0. what must be true about either a or b to make ab=0

The weight of an object in the water is 7% of its weight out of the water. what is the weight of a 652g object in the water?

Awater holding tank measures 105 m long, 50 m wide, and 8 m deep. traces of mercury have been found in the tank, with a concen- tration of 60 mg/l. what is the total mass of mercury in the tank? answer in units of kg.