1. Seventh Grade Geometry Unit 5

2. Properties of Triangles

3. Warm Up
One of two complementary angles has a measure that is five times the other angle.
Complementary angles add up to _________.
Write the equation in order to solve for the angle measurements.___________
X = ________________
The two angle measurements are __________ and ___________.

4. CC.7.G.2. Draw (freehand, with ruler and protractor, and with technology) geometric shapes with given conditions. Focus on constructing triangles from three measures of angles or sides, noticing when the conditions determine a unique triangle, more than one triangle, or no triangle.

5. Essential Questions
What are the characteristics of angles and sides that will create triangles?

6. Who uses this?

7. Discovery
Take the straws out of your envelope and measure them. Tape the straws together to form a triangle. Tape it to your paper and trace the inside. Measure the side lengths to make sure they match your original measurements. Label your triangle with those measurements. Take the protractor and measure the angles. Label the angles with those measurements. Discuss the similarities among the triangles at your table. Tables rotate around discussing the similarities of the triangles at the other tables.

11. Closing
What did you notice about the sides of triangles with the same angle measurements?
Similar triangles have the same angle measurements, but the sides are proportional.

12. Vocabulary
How do we classify angles in a triangle based on its sides?

13. Isosceles Triangles

14. Vocabulary
How do we classify angles in a triangle based on its sides?

15. How do we classify angles in a triangle based on its angles?
Equilateral or