1. In this lesson you will learn how to prove or disprove that 4 points in the coordinate plane make a rectangle.

2. Quadrilaterals No sets of parallel sides: Kites 1 set of parallel sides: Trapezoids 2 sets of parallel sides: Parallelograms No Right Angles: Rhombus or just a parallelogram 4 Right Angles: Rectangles

3. Parallelograms 1) If a quadrilateral has one pair of sides that are both parallel and congruent, then the quadrilateral is a parallelogram. 2) If a the opposite sides of a quadrilateral are congruent, then then quadrilateral is a parallelogram. 3) Opposites sides are parallel. 4) Opposite angles are congruent 5) Diagonals bisect each other. Quadrilaterals No sets of parallel sides: Kites 1 set of parallel sides: Trapezoids 2 sets of parallel sides: Parallelograms No Right Angles: Rhombus or just a parallelogram 4 Right Angles: Rectangles

4. Rectangle Has 4 right angles If you can prove one is a right angle then all have to be right. A square is a type of rectangle so doesn’t matter if it is a square or rectangle both are rectangles. Quadrilaterals No sets of parallel sides: Kites 1 set of parallel sides: Trapezoids 2 sets of parallel sides: Parallelograms No Right Angles: Rhombus or just a parallelogram 4 Right Angles: Rectangles

5. Prove or disprove that points A(1,6) B(-5,-2) C(-1,-5) D(5,3) form a rectangle.

6. Prove or disprove that points A(1,6) B(-5,-2) C(-1,-5) D(5,3) form a rectangle.

7. If any one of these statements had failed at any point along the way then we would have disproved that it was a rectangle.

8. In this lesson you learned how to prove or disprove that 4 points in the coordinate plane make a rectangle.