This document provides information about classifying triangles according to their sides and angles. It discusses scalene, isosceles, equilateral, acute, right, and obtuse triangles. Examples of classifying triangles based on their properties are provided. Students are instructed to draw triangles with given side or angle measures and classify triangles they draw on their own. The document also covers properties of quadrilaterals such as parallelograms, rectangles, rhombuses, squares, and trapezoids.

1. Classifying Triangles
Subject: Geometry
Grade Level: 7th
grade

2. Antonetti Triangle Notes
• Fold page in ½
• Students will take notes on one side and draw
on the other.

3. Where can you find TRIANGLES?
• Watch Animoto video!

4. Properties of TRIANGLES?
• Watch Discovery Ed video!

5. Two Ways to Classify Triangles

6. Classifying Triangles
By Their Sides
• Scalene
• Isosceles
• Equilateral

7. Scalene Triangles
• No sides are the same length

8. Isosceles Triangles
• At least two sides are the
same length

9. Equilateral Triangles
• All sides are the same
length

10. Two Ways to Classify Triangles

11. Classifying Triangles
By Their Angles
• Acute
• Right
• Obtuse

12. Acute Triangles
• Acute triangles have
three acute angles

13. Right Triangles
• Right triangles have One
right angle

14. Obtuse Triangles
• Obtuse triangles have ONE
obtuse angle

15. Classify this triangle.
Right
Scalene

16. Classify this triangle.
-
Obtuse
Isosceles

17. Classify this triangle.
Acute
Scalene

18. Classify this triangle.
Acute
Isosceles

19. Classify this triangle.
Obtuse
Scalene

20. Triangle Degrees
• The sum of the measures of
any triangle is 180°.
70°
x
What is the
measure of x?

21. Triangle DegreesTriangle Degrees
45°
x
What is the
measure of x?

22. Triangle Degrees
What is the
measure of x?
x
60° 50°

23. Side Measures
• Draw triangles given 3 side measures.
– “You Want Me to Do What?!” Worksheet

24. Angle Measures
• Protractor Practice:
– How to Use a Protractor
– Independent Practice measuring angles and
constructing angles
• Construct triangles given (3) angle measures.
• “Construct Triangles with Angle Measures”
worksheet

25. Create Your Own
• On a Scrap sheet of paper you need to:
• Draw 3 triangles
– 3 Different Sizes - Very Precise
– Measure Sides and Angles (Label)
– Put in a chart (See my example)
• Classify Each triangle according to your notes.
Triangle <1 <2 <3 Sum
Classification
by Angles
Side
1
Side
2
Side
3
Classification
by Sides
1
2
3

27. Quadrilateral Flowchart
Give Student’s a
copy of
Flowchart…
Brainstorm
with your
partner:
Use the word
bank to
complete the
Flowchart?
Rectangle
Rhombus
Trapezoid
Quadrilateral
Parallelogram
Square

28. Quadrilateral Flowchart

29. What is a quadrilateral?What is a quadrilateral?
A quadrilateral is a closed 2 dimensional
figure with FOUR (4) line segments.

30. What is a parallelogram?What is a parallelogram?
Opposite sides congruent
Opposite sides parallel

31. What is a rectangle?What is a rectangle?
Four right angles.

32. What is a rhombus?What is a rhombus?
Four congruent sides.

33. What is a square?What is a square?
4 right angles
4 sides congruent

34. What is a trapezoid?What is a trapezoid?
 Exactly one pair of parallel sides

35. What are all of the names for this polygon?What are all of the names for this polygon?
Quadrilateral
 Parallelogram
 Rectangle
Which name best describes the shape?

36. What are all of the names for this polygon?What are all of the names for this polygon?
Quadrilateral
 Parallelogram
Which name best describes the shape?

37. What are all of the names for this polygon?What are all of the names for this polygon?
Quadrilateral
 Parallelogram
 Rhombus
Which name best describes the shape?

38. What are all of the names for this polygon?What are all of the names for this polygon?
Quadrilateral
 Trapezoid
Which name best describes the shape?

39. What are all of the names for this polygon?What are all of the names for this polygon?
Quadrilateral
 Parallelogram
 Square
Rhombus
Rectangle
Which name best describes the shape?