Download Classifying Triangles Using Sides and Angles Name

Math Diagnosis and
Intervention System
Name
Intervention Lesson K41
Classifying Triangles Using Sides and Angles
Example 1
Describe triangles by their sides.
This is an equilateral
triangle. All sides are
the same length.
This is an isosceles
triangle. At least two
sides are the same length.
This is a scalene
triangle. No sides are
the same length.
Example 2
Name the triangles by the kinds of angles they have.
This is a right triangle.
It has exactly one
right angle.
This is an acute
triangle. It has
3 acute angles.
This is an obtuse
triangle. It has exactly
one obtuse angle.
Tell if each triangle is equilateral, isosceles, or scalene.
© Pearson Education, Inc.
1.
2.
3.
Tell the number of sides that are the same length for each triangle.
4. scalene
5. equilateral
6. isosceles
81
Math Diagnosis and
Intervention System
Name
Intervention Lesson K41
Triangles (continued)
Tell if each triangle is right, acute, or obtuse.
7.
8.
9.
10. How many acute angles does an acute triangle have?
11. How many obtuse angles does an obtuse
triangle have?
12. How many right angles does a right triangle have?
13. Reasoning How many acute angles does
a right triangle have?
14. Describe this triangle by its sides and by its angles.
(Hint: Give it two names.)
Test Prep Circle the correct letter for the answer.
15. Which term describes this triangle?
B Right
C Equilateral
D Obtuse
16. How many sides of an isosceles triangle are the same length?
A One
82
B Two
C Three
D None
© Pearson Education, Inc.
A Acute