Download proof page - Aurora City Schools

PROOF PAGE
Definitions:
Linear Pair - adjacent angles formed by two intersecting lines
Supplementary Angles - angles whose sum is 180o
Vertical Angles - two angles whose sides form opposite rays
Perpendicular Lines - form a right angle
Right Angle - formed by perpendicular lines and measures 90o
Complementary Angles - angles whose sum is 900
Postulate - a statement accepted as fact without proof
Theorem - a statement that must be proven true
Midpoint – divides a segment into two equal pieces
Perpendicular bisector – creates a midpoint and perpendicular lines (a right angle)
Postulates and Theorems:
Linear Pair Postulate - If two angles are a linear pair, then the sum of their measure is 180o
Vertical Angles Theorem - vertical angles are equal
Angle Addition Postulate - the sum of two smaller angles is the equal to the whole angle
If a point lies on the perpendicular bisector of a segment, then it is equidistant from the
two endpoints
Alternate Interior Angle Theorem - If two lines are parallel, then alternate interior angles
are equal
Alternate Exterior Angle Theorem - If two lines are parallel, then alternate exterior angles
are equal
Corresponding Angle Theorem - If two lines are parallel, then corresponding angles are
equal
Same Side Interior Angle Theorem - If two lines are parallel, then same side interior angles
are supplementary
Same Side Exterior Angle Theorem - If two lines are parallel, then same side exterior angles
are supplementary