Find the reference angle for the given angle:
780 degrees

Solve the system of equations. y= 2x y= x^2 - 15

Franco wants to double the volume of the cone. what should he do?

Determine the number of outcomes in the event. decide whether the event is a simple event or not. upper a computer is used to select randomly a number between 1 and 9 comma inclusive. event upper b is selecting a number greater than 4. event upper b has nothing outcome(s). is the event a simple event? (yes or no) because event upper b has (fewer than, exactly, more than) one outcome.