Triangles. Classification and properties

• New lesson editor
• Wiskunde
• Middelbare school
• vwo
• Leerjaar 1

Starting task:

Triangles

Learning objectives:

At the end of this lesson I can:

 -Identify different types of Triangles

-Use the angle sum property to find unknown angles in triangles.

What do you know about triangles?

Classification of triangles

Name the triangle according to its angles and sides

Name the triangle according to its angles and sides

Activity: Tearing a Triangle

a Take two triangles from the bag.

b Color the corners of the triangle just like in the figure below.

c  Tear off the corners of the triagle. Place them next to each other and stick them in your notebook.

5

minute

00

second

+30 s

Conclusions from activity

what kind of angle is this?

Sum Angle Property

Find the missing angle:

Find the missing angle:

Find the missing angle

Find the missing angles

A

34

B

46

C

36

D

44

Find the missing angle

A

54

B

44

C

34

D

64

Try yourself

In teams you have a worksheet named:

"Sum of angles in a triangle"