1. Angles

2. Triangles  Ever notice that the word triangle has the word “angle” in it? The shape is actually called “three angles”  Draw any four sided shape  Try to divide it evenly to make perfect triangles in it  Are there any four sided shapes that this doesn’t work for?  Draw any type of triangle  Try to divide it evenly to make perfect squares or rectangles in it  Does it work?  What type of conclusion can you make from this?

3. Why triangles?  The importance of the triangle to mathematics and the world around us is absolutely tremendous.  For instance, the triangle is the basic building block of all two-dimensional polygons, including rectangles, squares, rhombuses, and kites.  Triangles are also of great significance in our everyday lives. The buildings around us and the bridges we ride over are guaranteed to have triangles in their construction. Moreover, the trigonometry behind triangles has advanced some of the latest developments in technology including GPS systems, satellite imagery, and cell phone frequencies

4. Proof  Find examples around the circle that have hidden triangles at work.  Go!

5. My Proof

11. But wait…  Before we can really understand and classify triangles, we need to understand angles

12. Learning Goal  LG: Demonstrate an understanding of angles  Kid Friendly: Show that you understand what angles are  What I think I know:  Why I think this matters:

13. Definition  An angle measures the amount of turn  These are some examples of what angles can look like

14. Measurement of Angles  Angles can be measured using a protractor  It helps you measure angles in degrees  http://www.mathsisfun.com/geometry/protractor-using.html

15. 90 Degrees  A 90 degree angle makes a perfect L shape. Protractors usually have two sets of numbers going in opposite directions. Be careful which one you use! When in doubt think "should this angle be bigger or smaller than 90° ?"

16. Try…  Drawing an angle at:  30 degrees  60 degrees  90 degrees  120 degrees  150 degrees  180 degrees

17. Four Sided Shapes (Quadrilaterals)A: Measurement of every angle B: Total sum of every angle A: B: A: B: A: B: A: B:

18. Three Sided Shapes (Triangles)A: Measurement of every angle B: Total sum of every angle A: B: A: B: A: B: