Types of Triangles Equilateral: it is the triangle that all sides are the same. Equiangular: it is the triangle that all angles are the same. Isosceles: it is the triangle that has two equal sides only. Scalene: it is the triangle that has no equal side
Types of Triangles Right Triangle: a triangle with only one right angle in it. Acute Triangle: all angles are acute, less than 90 degrees Obtuse Triangle: a triangle where one of the angles is obtuse.
The Parts of a Triangle & Triangle Sum Theorem A triangle has three angles and three sides. The triangle sum theorem is that all angles sum up to 180 degrees. =180 82 142 =180 8 19 90 19 60 =180 60 60
Exterior Angles Theorem The Exterior Angle always sums up to the two non adjacent sides. 60 45 60 120 135 90 100 130 30
CPCT Stands for Corresponding Parts of a Congruent Triangle. This means that is two triangles are congruent, all the corresponding parts will also be congruent 1 4 A D Triangle ABC is congruent to triangle DEF. Therefore, all parts will also be congruent 3 5 2 6 C F E B Triangle 123 is congruent to triangle 456. Therefore, all parts will also be congruent. d b a Triangle abc is congruent to triangle def. Therefore, all parts will also be congruent. c e f
Side-Side-Side Postulate SSS postulate: If two triangles have three congruent sides, the triangles are congruent.
Angle-Angle-Side Postulate If two angles and a non included side are congruent to the two angles and a non included side of another triangle then the two triangles are congruent.
Angle-Side-Angle Postulate If two angles and the side between them are congruent to the other triangle then the two angles are congruent.
Side-Angle-Side Postulate If two sides and the adjacent angle between them are congruent to the other triangle then those triangles are congruent.