Sheryltalidongid Sheryltalidongid Math Answered 3. Choose the letter of the ratio that will make a proportion.1.2 : 42.3 :73. 7:24. 4:105. 18:6a. 4 : 16a. 9:21a. 3:1a. 5:6a. 5:1b. 12 : 24b. 3 : 14b. 21 : 7b. 2:5b. 3:1c. 3 : 15c. 4 :7c. 14:4c. 3:4c. 4:3