Lines LaTeX: ACA C and LaTeX: DFD F are parallel. They are cut by transversal LaTeX: HJH J. 3 lines.Â
Find the seven unknown angle measures in the diagram. Explain your reasoning.

What do you notice about the angles with vertex LaTeX: BB and the angles with vertex LaTeX: EE?
Using what you noticed, find the measures of the four angles at point LaTeX: BB in the second diagram. Lines LaTeX: ACA C and LaTeX: DFD F are parallel.

3 lines in a plane.Â
The next diagram resembles the first one, but the lines form slightly different angles. Find the six unknown angles with vertices at points LaTeX: BB and LaTeX: EE.

Three lines in a plane.Â
What do you notice about the angles in this diagram as compared to the earlier diagram? How are the two diagrams different? How are they the same?