Properties of Triangles
Triangles can be classified (named) two ways – by their angles and their side
Classifying Triangles by Angles –
Triangle
Property
Drawing
Acute Triangle
Right Triangle
Obtuse Triangle
Classifying Triangles by Side
Triangle
Equilateral Triangle
Isosceles Triangle
Scalene Triangle
LengthsProperty
Drawing
lengths.
Properties of Triangles
Classify the triangle by its angles.
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Another important fact regarding triangles is that they ALL have the same angle sum. Meaning, when
you add together the 3 angles, you will always get the same amount. Based on our investigation, what is
the sum of angle measures of any triangle? ____________
Using the information above, tell whether the angle measures can be those of a triangle.
a.
15°, 160°, 15°
Find the value of x.
b. 22°, 92°, 66°
c. 102°, 12°, 65°
Properties of Triangles
Match the vocabulary word with its description.
_____ 1. Acute triangle
A. a triangle has one 90° angle
_____ 2. Right triangle
B. a triangle that has two sides of equal length
_____ 3. Obtuse triangle
C. a triangle that has three sides of different lengths
_____ 4. Equilateral triangle
D. a triangle that has three angles that are smaller than 90°
_____ 5. Isosceles triangle
E. a triangle that has one angle that is larger than 90°
_____6. Scalene triangle
F. a triangle that has three sides of equal length