B. 30. Which of the following pairs of ratios form a proportion? a 18:21 and 12:14 b. 4 5 and 10:8 c.5: 11 and 18 : 13 d. 6 : 5 and 10 : 8 31. In the proportion, 59 = N: 63, find the value of N. a 14 b. 7 C. 115​