If two angles are supplementary to congruent angles (or to the same angle), then they are congruent.
Theorem 1-2 Congruent Supplements Theorem
90° angle, created at the intersection of two perpendicular straight lines
Right angle
Midpoint formula
a location and has no size
Can draw a straight line using a straight edge
Axiom #1
If a transversal intersects two parallel lines, then corresponding angles are congruent.
Two angles that, when added together, form 180°
Supplementary angles
(x,y) > (y, -x)
Rotation of 90° clockwise
bisects all sides at 90°
Circumcenter
Things that are congruent are equal to one another
Common Notion #4
If two sides of a triangle are congruent, then the angles opposite those sides are congruent.
Theorem 4-1 Isosceles Triangle Theorem and the Converse
Two angles that, when added together, form 90°
(x, y) > (-x, -y)
Rotation of 180° clockwise and counterclockwise
equal, but may be off by a decimal
Congruent
All right angles are congruent
Axiom #4
If the hypotenuse and one leg of a right triangle are congruent to the hypotenuse and leg of another right triangle, then the triangles are congruent.
Theorem 4-8 Hypotenuse Leg Theorem
If a transversal intersects two parallel lines, then ________ are congruent.
Corresponding angles
(x, y) > (-y, x)
Rotation of 270° clockwise
formed by two rays with the same endpoint
angle
If A = B and B = C, then A = C (Transitive Property)
Common notion #1
If a point is on the bisector of an angle, then the point is equidistant from the sides of the angle.
Theorem 5-4 Angle Bisector Theorem
Each of the pairs of opposite angles made by two intersecting lines.
Vertical angles
a2 + b2 = c2
Pythagorean Theorem
bisecting angles
Incenter
The whole is greater than its part
Common notion #5