Answer:
100 degrees.
Step-by-step explanation:
The missing angle on the bottom triangle is equal to 80 degrees because a triangle's interior angles add up to 180deg.
Think of that middle angle between angle 1 and the two triangles as a full 360deg. Since VAT (Vertical Angle Theorem) suggests that vertical angles are equal, 160deg of that 360deg are taken up by the missing angles in the triangles. That leaves 200deg to split between angle 1 and its equal vertical angle, which means angle 1 is 1/2 of 200, or 100deg.
