Name __________________________________
Classifying Triangles Section:
Parts of a Triangle: A triangle is a three-sided polygon:
Name this triangle using the vertexes
____________________________________.
Name two sides of this triangle –
_________________
___________________.
Name two angles of this triangle.
__________________
____________________.
Classifying Triangles: Please write the letter of the definition that corresponds to
the geometric term.
____ Acute ∆
a) A triangle that has one angle that measure between 90
and 180 degrees.
____ Obtuse ∆
b) A triangle that has one angle that measures exactly 90
degrees.
____ Right ∆
c) A triangle that has all angles that measures between 0
and 90 degrees.
____ Scalene ∆
d) A triangle that has all sides that are equal.
____ Isosceles ∆
e) A triangle that has no sides equal.
____ Equilateral ∆
f) A triangle that has at least two sides equal.
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Question 1: Find x and the measure of each side of equilateral triangle RST.
x = ____________
Measure of RT = ____________
Measure of RS = ____________
x+8
Measure of ST = ____________
4x - 16
Angle Sum Theorem:
The sum of the measures of the angles of a ___________________ is
__________.
Find the missing angle measures.
Measure of Angle “?” = ______________
A
Measure of Angle “A” = ______________
120
Exterior Angle Theorem:
m∠C =
_______________
m∠D =
_______________
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Isosceles Triangle Theorem: If two sides of a triangle are __________________,
then the angles opposite those sides are ____________________.
A triangle is _____________________ if and only if it is ___________________.
Each angle of an equilateral triangle measures ________.
∆EFG is equilateral, and EH bisects ∠E.
a.)
m∠1 = _____________
b.)
m∠2 = _____________.
c.)
x = _____________
6x
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In the following figure, QR = 12, RS = 23, QS = 24, RT = 12, TV = 24, and RV
= 23.
Name one pair of corresponding congruent angles.
_______________________________
Name one pair of corresponding sides.
________________________________
Proving Congruence with SSS, SAS, ASA or AAS.
Use SSS or SAS to prove the following.
Extra Credit
1) Is there an ASS Postulate? Give an example or counterexample.
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