Math 8 Ms. Stewart Unique Triangles

Terminology/Notation Review Symbol Meaning Example In words Triangle ABC ABC has three equal sides Angle A Angle A is equal to …. AB Line Segment The line between A and B Congruent (same shape and size) Triangle ABC is congruent to triangle DEF

What is a unique triangle? a triangle that is one-of-a-kind any other triangle constructed using the same specific set of instructions will be congruent to the original triangle

What makes a figure congruent? two figures are said to be congruent if they have the same shape and size all corresponding sides are equal in length and all corresponding angles are equal in measure

Conditions for a Unique Triangle All side lengths of the triangle are known (S-S-S) When all side lengths of a triangle are known, the triangle is said to be unique. For example: Draw a triangle with side lengths of 6 cm, 7cm and 9 cm.

Conditions for a Unique Triangle The lengths of two sides and the measure of the angle between those two sides is known (S-A-S) Example:

Conditions for a Unique Triangle The measure of two angles and the length of the side between the angles (A-S-A). Example:

Conditions for a Unique Triangle The measure of two angles and the length of a side not between the angles (A-A-S) Example:

Practice Question