Answer:
1. the total triangles of 12 sides are 10 triangles but the exterior angles of a 12 sided polygon is 30° because dodecagon is equal to 150°
2. the total triangles of 18 sides are 16 triangles but the exterior angles of a 18 sided polygon is 20° because octakaidecagon is equal to 360°/18=20°
3. the total triangles of 8 sides are 6 triangles but the exterior angles of a 6 sided polygon is 120° because hexagon is equal to 720°/6=120°
4. the total triangles of 3 sides are 1 triangle but the exterior angles of a 6 sided polygon is 60° because hexagon is equal to 180°/3=60°