(100 points)which pair of ratios form a proportion? 5 : 11 and 6 : 127 : 13 and 21 : 398 : 14 and 24 : 3010 : 20 and 20 : 30

5/11 and 6/12

Cross multiply.5 * 12 = 11 * 660 = 66This is UNTRUE, so this does not form a proportion.

7/13 and 21/39

Cross multiply.7 * 39 = 13 * 21273 = 273This is TRUE, so this forms a proportion. Let's keep going to make sure that this is our answer.

8/14 and 24/30

Cross multiply.8 * 30 = 14 * 24240 = 336This is UNTRUE, so this does not form a proportion.

10/20 and 20/30

Cross multiply.10 * 30 = 20 * 20300 = 400This is UNTRUE, so this does not form a proportion.

Your answer is 7 : 13 and 21 : 39 are a pair of ratios that form a proportion.