Unit 2 - Lesson 8 - Grade 8: Illustrative Mathematics

Create three different expressions that are each equal to 20. Each expression should include only these three numbers: 4, -2, and 10.

After you have created your triangle, measure each side length with a ruler and record the length. Then measure the angles to the nearest 5 degrees using a protractor and record these measurements.

Find two others in the room who have the same angle A and compare your triangles. What is the same? What is different? Are the triangles congruent? Similar?

How did you decide if they were or were not congruent or similar?

After you have created your triangle, measure each side length with a ruler and record the lengths. Then measure the angles to the nearest 5 degrees using a protractor and record these measurements.

Find two others in the room who used your same angles and compare your triangles. What is the same? What is different? Are the triangles congruent? Similar?

How did you decide if they were or were not congruent or similar?

Is your new pasta triangle PST similar to ΔPQR ? Explain your reasoning.

If your broken piece of pasta were a different length, would the pasta triangle still be similar to ΔPQR? Explain your reasoning.

Explain how you know each of these three triangles is similar to DJI.