Page 125 - Math Course 2 (Book 2)

Classifying Triangles

MO. 10 - L2b acute triangle
A triangle that has all angles less than 90°.
Properties and Attributes

of a Triangle 70° 83°

Vocabulary A-Z 60° 50° 21° 76°

Let us learn some vocabulary
obtuse triangle
A triangle that has an angle greater than 90°.
acute angle
An acute angle is less than 90°.
20° A
50° 49°
110°
20° 111°
B C

right triangle
A triangle that has a right angle (90°).

right angle 90°

A right angle is an internal angle which is equal to 90°. 90°

90° congruent
Congruent means the same size or length.
Triangles can be classified by their angles and
straight angle their sides. Congruent sides have the same length.
A straight angle is 180°. C
65°
180°
A 75° B
45° 45° 10cm

obtuse angle scalene triangle
An obtuse angle is more than 90° but less than 180°. A triangle with no congruent (equal) sides or
angles.No sides are equal and no angles are equal.

A

130°
15 104° 11

B 30° 20 46° C

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