Identify them as complementary supplementary vertical or adjacent

Find the missing number. a. 3 : 24 = : 72 b. : 18 = 5 : 9 c. 6: = 36 : 36

Which one ? is the answer and how to find this answer

David estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x. create a question you could ask that could be answered only by graphing or using a logarithm.