well, im assuming its talking about a triangle. The total number of degrees is 180. I guess you subtract that by 81. You get 99. But there are still the others. Srry this is how far i can help. But you then go with 99 and divide or sum thing.
Explanation is in a file

Answer:
- 984 adults
- 281 teens
- 492 children
Step-by-step explanation:
Multiply the total by the corresponding percentage to find the number. We assume the percentages have been rounded, so some adjustment is needed in the result of the multiplication.
{adults, teens, children} = 1757 × {.56, .16, .28} = {983.92, 281.12, 491.96}
≈ {984, 281, 492}
The visitors included 984 adults, 281 teens, and 492 children.
6 4/9, hope this helps tell me if you need and explanation