triangle
A 3 sided polygon.
polygon
A closed figure formed by three or more line segments
acute triangle
A triangle with 3 acute angles
right triangle
a triangle with 1 right angle
obtuse triangle
A triangle with 1 obtuse angle
equiangular triangle
A triangle with 3 congruent angles each measure 60 degrees
scalene triangle
A triangle with no congruent sides.
isosceles triangle
A triangle with at least 2 congruent sides
equilateral tringle
A triangle with 3 congruent sides
Interior Angle Sum Thm
The sum of the interior angles of a triangle is 180 degrees
Exterior Angle Thm
The measure of the exterior angle of a triangle is equal to the sum of the two remote interior angles
Isosceles Triangle Thm
The base angles of an isosceles triangle are congruent
congruent triangles
2 triangles are congruent if and only if all pairs of corresponding sides and angles are congruent
SSS
If 3 sides of one triangle are congruent to 3 sides of another triangle, then the triangles are congruent
SAS
If 2 sides and an included angle of a triangle are congruent to 2 sides and included angle of aother triangle, then the triangles are congruent
ASA
If 2 angles and an included side of a triangle are congruent to 2 angles and included side of another triangle, then the triangles are congruent
AAS
If 2 angles and a non-included side of one triangle are congruent to 2 angles and a non-included side of another triangle, then the triangles are congruent
HL
If the hypotenuse and a leg of one right triangle are congruent to the hypotenuse and leg of another right triangle, then the triangles are congruent.
CPCTC
If two triangles are congruent, then their corresponding parts are congruent.
median of a triangle
A segment from a vertex to the midpoint of the opposite side.
altitude of a triangle
The perpendicular segment form a vertex to the line containing the opposite side.
Similar Triangles
Two triangles with corresponding angles equal and corresponding sides proportional