1. 4.8 Triangles and Coordinate Proofs

2. Coordinate Proofs
Coordinate proofs use figures in the coordinate plane and algebra to prove geometric concepts. The first step in a coordinate proof is placing the figure on the coordinate plane.

3. Example 1
a) Position and label right triangle XYZ with leg d units long on the coordinate plane.

4. Example 1
b) Which would be the best way to position and label equilateral triangle ABC with side w units long on the coordinate plane?

5. How To Place Triangles on a Coordinate Plane

6. Example 2
Name the missing coordinates of isosceles right triangle QRS.

7. Example 3
Position an isosceles triangle on the coordinate plane so that its sides are a units long and one side is on the positive x-axis.

8. Example 4
Name the missing coordinates of each triangle.

9. Example 4
Name this missing coordinates of each triangle.

10. Example 4
Name the missing coordinates of each triangle.

11. Example 5
Position and label each triangle on the coordinate plane. a) isosceles triangle △RST with base (RS) 4a units long

12. b. isosceles right △DEF with legs e units long

13. c. equilateral triangle △EQI with vertex Q(0, √3b) and sides 2b units long

14. Summary

15. Summary

16. Summary