Water is flowing from a tap at the base of a cylindrical tank at a constant rate. ryan wants to determine the time it will take to empty the tank. which measurement(s) should ryan use?

As the water leaves the tank, the water level will change, so the volume of the water will change accordingly. The volume of water at any time is determined by the radius of the tank and the water level at that time. Since the tank's radius is constant, Ryan only needs to check the water level (i.e. measure the height of the surface of water from the bottom of the tank.

The power of the root of the power of a variable can be written as a rational power by creating a rational exponent that is the product of the powers divided by the root. The rational exponent should be reduced to lowest terms. For example, the seventh power of the sixth root of the fifth power of x will be x^(7*5/6) = x^(35/6).
hope it helps