Answer: Down Below ↓
Step-by-step explanation: Here's an easy tip for measuring the angles of triangles. Every triangle has a sum (total) of 180 degrees. Take the two angles that are already shown, add them together, then subtract them from 180.
I cannot read the numbers on the paper, so I hope this answer somewhat helps.
Edit: Oh my lord, it's a coloring page too? I remember those, they suck. :')