Answer
C = 12
Step-by-step explanation
Ratio is a division. For the two ratios to be proportional, then they must be the same after been simplified to their simplest form.
7/C = 35/60
35 has been divided by 5 to get 7. 60 must also be dived by 5 for the ratios to be proportional.
60 ÷ 5 = 12
∴ C = 12.
7/12 = 35/60