Answer:
87
Explanation:
So there are 5 numbers listed. You can obviously see the two small sides are 9. They are the same size. Then you have the three 9s on the top. This is important. So far we are at 75ft. The complication comes in at what is the unknown side. Well if you see the three 9s on top. Two are going horizontal along with the 30. So 9+9 is 18. 30-18 is 12. So that side is 12. Answer is 87.
Hope this helps