1. Proving Parallelograms: Coordinate Geometry Unit 1C3 Day 4

2. Do Now For two points in a coordinate plane, (x 1, y 1 ) and (x 2, y 2 )…  What is the distance formula?  What is the slope formula?  What is the midpoint formula?

3. Using Coordinate Geometry  When a figure is in the coordinate plane, you can use the ________________________ to prove that sides are congruent.  You can use the _____________________ to prove sides are parallel.

4. Ex. 1: Using properties of parallelograms  Show that A(2, -1), B(1, 3), C(6, 5) and D(7,1) are the vertices of a parallelogram.

5. Ex. 1a: Using properties of parallelograms  Method 1—Show that opposite sides have the same slope, so they are parallel.

6. Ex. 1b: Using properties of parallelograms  Method 2—Show that opposite sides have the same length.

7. Ex. 1c: Using properties of parallelograms  Method 3—Show that one pair of opposite sides is congruent and parallel.

8. Ex. 1d: Using properties of parallelograms  Method d— Show that diagonals bisect each other.

9. Ex. 2: Proving Parallelograms

10. Closure  Could a hexagon with opposite sides parallel be called a parallelogram? Explain.