1.	In mathematics, a ratio is a comparison of two numbers by ______.
		A.	subtraction	B.	addition
		C.	multiplication	D.	division
		Hint
	2.	An equation stating that two ratios are equal is called a(n) ______.
		A.	equivalent equation	B.	proportion
		C.	cross product	D.	rate
		Hint
	3.	Every proportion has two cross products which are always ______.
		A.	positive	B.	zero
		C.	negative	D.	equal
		Hint
	4.	Solve the proportion =
		A.	20	B.	13.5
		C.	80	D.	6
		Hint
	5.	Solve the proportion =
		A.	-18	B.
		C.	4.5	D.
		Hint