1. Proving a quadrilateral is a RHOMBUS
Using coordinate geometry…

2. To prove a quad. is a Rhombus:
Use the slope formula a total of 6 times to
show that
1) BOTH pairs of opposite sides are parallel (4)
(have the same slope)
AND
2) BOTH diagonals are perpendicular (2)(have negative
reciprocal slopes)
Concluding statement: Quad. is a rhombus bc both pairs of opposite sides are parallel and diagonals are perpendicular

3. OR – ANOTHER WAY IS
Use the distance formula 4 times to show that all sides have the same length (they are congruent).
Concluding statement: It’s rhombus bc all sides congruent.