Question# 1. Polygon angle sum (irregular polygon)
Question# 2. Triangle inequality (relating angles)
Question# 3. No video.
Question# 4. Triangle inequality (Sum of any two sides greater than the third side)
Question# 5. Solving a quadratic
Question# 6. Reflection
Question# 7. Rotation
Question# 8. Composition of transformations (Dilation followed by translation)
Good luck.