Through (1,-6) and perpendicular to y=-3x+3

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

With number 11 ( show how you got the answer)

What unit of been sure would be appropriate for the volume of a sphere with a radius of 2 meters