Unit 1 - Lesson 10 - Grade 8: Illustrative Mathematics

What can you say about the measures of angles B and C?

What kind of quadrilateral is ABCD?Explain how you know.

Describe a rigid transformation that takes Triangle 1 to Triangle 2. What points in Triangle 2 correspond to points A, B, and C in the original triangle?

Describe a rigid transformation that takes Triangle 1 to Triangle 3. What points in Triangle 3 correspond to points A, B, and C in the original triangle?

Find two pairs of line segments in the diagram that are the same length, and explain how you know they are the same length.

Find two pairs of angles in the diagram that have the same measure, and explain how you know they have the same measure.

How long is... How do you know?

If you continue to reflect each new triangle this way to make a pattern, what will the pattern look like?