Answer: on the toss side the missing number is 50 and on the dollar side the missing number is 4.
On the dollars side I subtracted 8 from 12 and got 4. 4 doubled is 8 so then I doubled 25 and got 50. every 25 rings costs 4 dollars so as you increase by 25 you also increase by 4. For graphing you treat tosses like the X value and you treat the dollars as the Y value.
I hope this makes sense and I hope this helps!