1. Angle Relationships in Triangles
1.1. auxillary-a line drawn in a figure to aid in a proof.
1.1.1. coroallary-a theorem whose proof follows directly from another theorem
1.1.1.1. interior-an angle formed by two sides of a polygon with a common vertex.
1.1.1.1.1. exterior-an angle formed by one side of a polygon and the extension of an adjacent side.
2. Congruent triangles
2.1. corresponding angles-angles in the same relative position in two different polygons that have the same number of angles.
2.1.1. corresponding sides-sides in the same relative position in two different polygons that have the same number of sides.
2.1.1.1. congruent polygons-two polygons whose corresponding sides and angles are congruent.
3. Triangle Congruence:SSS and SAS
3.1. triangle ridigy-a property of triangles that states that if the side lengths of a triangle can have only one shape.
3.1.1. included angle- the angle formed by two adjacent sides of a plygon.
4. Acute:A triangle with three acute angles
4.1. equiangular: A triangle with three congruent angles
4.1.1. Right: a triangle with one right angle
4.1.1.1. obtuse: a triangle with one obtuse angle
4.1.1.1.1. equilateral: a triangle with three congruent sides
5. Congruence and Transformations
5.1. dilation: a transformation in which the lines connecting every point p with its preimage p all intersect at point c
5.1.1. isometry: a transformation that does not change the size or shape of a figure