Cheat Sheet for Geometry Midterm
(only includes official postulates, theorems, corollaries and formulas)
points, lines, planes, intersections,
• Through any two points there is exactly one line.
• Through any three noncollinear points there is exactly one plane containing them.
• If two planes intersect, then they intersect in exactly one line.
• If two lines intersect, then they intersect in exactly one point.
linear pairs, supplements,
complements, vertical angles, right angles
• If two angles form a linear pair, then they are supplementary.
The sum of the measures of the angles of a linear pair is 180.
• If two angles are supplementary to the same angle or to two congruent angles, then the two
angles are congruent.
• If two angles are complementary to the same angle of to two congruent angles, then the two
angles are congruent.
• All right angles are congruent.
• Vertical angles are congruent.
parallel lines, angles formed by parallel lines and transversals,
perpendicular lines
• If two parallel lines are cut by a transversal, then corresponding angles are congruent.
• If two parallel lines are cut by a transversal, then alternate interior angles are congruent.
• If two parallel lines are cut by a transversal, then alternate exterior angles are congruent.
• If two parallel lines are cut by a transversal, then same side interior angles are
supplementary.
• If two lines are cut by a transversal so that corresponding angles are congruent, then the
lines are parallel.
• If two lines are cut by a transversal so that alternate interior angles are congruent, then the
lines are parallel.
(over)
