Find the cosine of ∠R. Simplify your answer and write it as a proper fraction, improper fraction, or whole number.
cos (R) =

1- 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. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?

Lines a and b are perpendicular. if the slope of line a is 3, what is the slope of line b?

Ethan purchased a container of sports drink that contains 300 calories. the label says that 80% of the calories are from carbohydrates. how many calories are from carbohydrates?