Describe the methods you can use to find the missing value in the proportion 8/12=2/?

I would cross multiply:

reduce the fraction into simplest form

8/12→2/3

2/3=2/x. cross multiply

2x=3 (2)

x=3

missing value is 3

or

you could find the decimal value of 8/12 which is 0.67

0.67=2/x

solve for x

0.67x=2

x=3

missing value is 3