Classifying Triangles
A triangle with all sides the same length is called what?
Which theorem states that the sum of the interior angles in a triangle is 180 degrees?
What is Triangle Sum Theorem
In an isosceles triangle, the base angles are always what?
Congruent
What are the 5 postulates used to prove triangles congruent?
SSS, SAS, ASA, AAS, HL
What does CPCTC stand for?
Corresponding Parts of Congruent Triangles are Congruent
A triangle with exactly two sides the same length is called what?
What is Isosceles Triangle?
If two angles of a triangle measure 45 degrees and 65 degrees, what is the third angle measure?
What is 70 degrees
What is the measure of each angle in an equilateral triangle?
60 degrees
If two sides and the included angle of one triangle are congruent to two sides and the included angle of another, what postulate applies?
SAS
What is the first step in any geometric proof?
Write the given information.
What type of triangle has one angle greater than 90 degrees?
What is Obtuse Triangle
The measure of one angle is twice another, and the third angle is 60 degrees. Find all three angles.
40 degrees, 60 degrees, and 80 degrees
If the vertex angle of an isosceles triangle is 40 degrees, what is the measure of each base angle.
70 degrees
Which postulate requires two angles and the non-included side to be congruent?
AAS
If AC bisects angle BAD, what can you conclude about the angles BAC and CAD.
That angle BAC is congruent to angle CAD.
You now have two congruent angles.
Classify triangle ABC if its side lengths are 8cm, 10cm, and 16 cm.
What is Scalene Triangle
In triangle ABC, if the measure of A is (3x + 15), the measure of B = (2x+25) and the measure of C is (x+10), find x.
x = 21.666666
or 65/3
In triangle XYZ, if angle X is congruent to angle Z, XY= (13x - 21), YZ = (8x-6), and XZ = (x+4), find the value of x and the measure of the each side.
x = 3
XY = 18
YZ = 18
XZ = 7
Which postulate only applies to right triangles?
HL (Hypotenuse-Leg)
In a proof, if two segments share a side, what reason justifies their congruency?
Reflexive Property
A triangle has vertices at A(1,2), B(4,6), and C(7,2). Classify it by its sides.
What is Isosceles Triangle
Two triangles are congruent if all corresponding angles are congruent. True or false?
False
If W (-10,4) , X(-3, -1), and Y(-5,11) classify triangle WXY by its sides.
WX = square root of 74
XY = square roof of 148
WY = square roof of 74
False
What are the three properties of congruence?
Reflexive
Symmetric
Transitive