both pair of opposite sides equal (with distance formula)
both pair of opposite sides parallel (with slope formula)
diagonals bisect each other (midpoints of diagonals are the same)
Back
altitude of a triangle
Front
joins a vertex PERPENDICULAR to the opposite side
Back
horizontal lines
Front
zero slope (are of the form y=#)
Back
median of a triangle
Front
joins a vertex to the MIDPOINT of the opposite side
Back
perpendicular lines
Front
have opposite reciprocal slopes
Back
distance formula
Front
Back
standard form of a line
Front
Back
ways to prove something is a rectangle
Front
has a right angle (opposite reciprocal slopes)
or diagonals are congruent