Triangles
10-8
Draw an example of each type of triangle on dot paper.
- isosceles 2. acute 3.obtuse 4. scalene
- right 6. equilateral 7. isosceles obtuse 8. scalene acute
Classify each triangle by the measure of its sides
and by the measure of its angles.
D E
F
Matching tick marks
indicate congruent sides.
65 ° 40 °
17 mm^75 °
27 mm
25 mm 60 °
60 ° 60 °
10 m
10 m 10 m 40 cm 40 cm
60 cm
106 °
37 ° 37 °
60 °
30 °
4 m
3 m
5 m
Triangles are classified by the lengths of their
sides and/or by the measures of their angles.
Sides
equilateral triangle (A)—all sides congruent
isosceles triangle (B)—two sides congruent
scalene triangle (C)—no sides congruent
Angles
acute triangle (D)—three acute angles
obtuse triangle (E)—one obtuse angle
right triangle (F)—one right angle
Triangles can also be classified by both the lengths of
their sides and by the measures of their angles.
Both Sides and Angles
isosceles right triangle (G)—two sides
congruent and one right angle
scalene obtuse triangle (H)—no sides
congruent and one obtuse angle
A
B C
G H
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