Unit 1 - Lesson 14 - Grade 8: Illustrative Mathematics

Find the measure of angle JGH. Explain or show your reasoning.

With your partner, find the seven unknown angle measures in the diagram. Explain your reasoning.

What do you notice about the angles with vertex B and the angles with vertex E ?

Using what you noticed, find the measures of the four angles at point B in the second diagram. Lines AC and DF are parallel.

The next diagram resembles the first one, but the lines form slightly different angles. Work with your partner to find the six unknown angles with vertices at points B and E.

What do you notice about the angles in this diagram as compared to the earlier diagram? diagram? How are the two diagrams different? How are they the same?

Find a rigid transformation showing that angles MPA and MQB are congruent.

Does your argument in the earlier problem apply in this situation? Explain.

Find the values of a, b, c, d, e, f, and g.