Types of Triangles
Angle Sum Properties
Congruence
Mixed Bag
Vocabulary
100
A triangle whose angles measure 30, 60, and 90 degrees.
What is a right triangle?
100
180 degrees
What is the sum of the interior angles of a triangle?
100
The five triangle congruence theorems/postulates.
What is SSS, SAS, ASA, AAS and HL?
100
True or False: If two triangles have three pairs of congruent angles, they are always congruent.
False (AAA does not prove congruence, only similarity).
100
The two congruent sides of an isosceles triangle.
What are the legs?
200
A triangle whose side lengths measure 2 cm, 2 cm, 2cm.
What is an equilateral triangle?
200
The sum of the two nonadjacent interior angles.
What is the measure of an exterior angle?
200
A theorem that does NOT always prove triangles congruent.
What is SSA or AAA?
200
What additional information is needed to prove two right triangles are congruent using the HL Theorem?
One leg and the hypotenuse must be congruent.
200
The angles of an isoceles triangle that are not the vertex angle.
What are the base angles?
300
A triangle whose angles measure 20, 140 and 20 degrees.
What is an obtuse triangle or what is an isosceles triangle?
300
The value of x if the measures of the interior angles of a triangle are 90 degrees, (4x - 5) degrees, and (3x + 11) degrees.
What is 12?
300
CPCTC
What is the acrynom for Corresponding Parts of Congruent Triangles are Always Congruent.
300
Two triangles share a common side. What property allows you to state that side is congruent to itself?
Reflexive Property
300
A statement that switches the hypothesis and conclusion of a conditional statement.
What is a converse?
400
A triangle whose angles measure 60, 60, and 60 degrees.
What is an equiangular triangle?
400
The measure of the exterior angle, (5x - 10) degrees, when the two nonadjacent interior angles measure 40 degrees and 3x degrees.
What is 115 degrees?
400
A pair of corresponding side lengths that are congruent if ∆CAT≅∆HAT.
What is CA ≅ HA or AT ≅ AT or TC ≅ TH
400
A student claims SSA proves triangle congruence. Why is this incorrect?
SSA does not always guarantee congruence because the angle might not be between the given sides, leading to ambiguous cases.
400
These have corresponding parts.
What are Congruent triangles?
500
A triangle that never has any equal side lengths.
What is a scalene triangle?
500
Solve for x if the exterior angle is (6x - 7) degrees, and the nonadjacent interior angles are 2x degrees and (103 - x) degrees.
What is 55 degrees?
500
By which theorem are these two triangles congruent? And what side would be congruent to side FG by CPCTC?
AAS and Side GH
500
If two angles of one triangle are congruent to two angles of another, what must be true about the third angles?
They are congruent (by the Triangle Sum Theorem).
500
If you know that two triangles are congruent, then the corresponding sides and angles of the triangles are congruent.
What is Corresponding Parts of Congruent Triangles are Congruent (CPCTC)?