Theorems

• Supplements of equal angles are equal.
• Supplements of the same angel are equal.
• Complements of equal angels are equal.
• Complements of the same angel are equal.
• Vertical angels are equal.
• All right angles are equal.
• If two angles form a linear pair and are equal then, each is a right angle.
• The bisector of an angle divides the angle into two angles, each ½ as large as the original angle.
• The bisector of a line segment divides the segment into two segments, each ½ as large as the original line segment.
• If two sides of a triangle have equal lengths, then the angles opposite those sides have equal measures, or the base angles of an isosceles triangle are equal.
• The bisector of the vertex angel of an isosceles triangle separates the triangle into two congruent triangles.
• The bisector of the vertex angle of an isosceles triangle is the perpendicular bisector of the base of the triangle.
• If two angles of a triangle have equal measures, then the side s opposite those angles have equal lengths.