Angles

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 2

Good morning!

Schedule: 

• Learning goals 
• Worksheet check
• Angles
• Angle notation
• Measuring angles

Learning goals 

At the end of this lessons I can:

• Identify different kinds of angles
• Use the correct notation when working with angles
• Measure angles with my protractor/geotriangle 

What different kinds of angles are there?

Acute angle

Right angle

Obtuse angle

Revolution

Reflex angle

Straight angle

90°

Between 0° and 90°

Between 90° and 180°

180°

Between 180 and 360°

360°

Angle notation

Three point notation: You refer to angles using a point on each arm and the vertex between them

Angle notation

Three point notation: You refer to angles using a point on each arm and the vertex between them

Arms

Angle notation

Three point notation: You refer to angles using a point on each arm and the vertex between them

Green angle notation : 

Blue angle notation : 

Red angle notation : 

Angle notation

Three point notation: You refer to angles using a point on each arm and the vertex between them

Green angle notation : 

ADB        or                BDA

Blue angle notation : 

BDC        or                CDB

Red angle notation : 

Reflex ADC

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You put a line over the vertex of the angle

Angle notation

Three point notation: You refer to angles using a point on each arm and the vertex between them

Other notations you might come across: 

∠ADB           ∠BDA

Other notations you might come across: 

∠BDC          ∠CDB

Other notations you might come across:

Reflex  of ∠ADC           reflex of ∠CDA

Book 

Open your book and take 10 min to finish: 

P. 48              3B:  1, 2

Done? 

P. 49                  3B: 3

Open this LessonUp and work on slide 14

Challenge

Challenge

Reflex ∠RQP         Reflex ∠XYZ         Reflex ∠ABC

Reflex ∠PQR         Reflex ∠ZYX         Reflex ∠CBA

Measuring angles

1. What kind of angle is it? What amount of degrees could it be? 

(Ex. An acute angle MUST be between 0° and 90°)

2. Measure with your protractor or geotriangle

3. Check: does my measurement make sense with step 1? 

Measuring and coloring !

Ask for a worksheet from the supervisor!

(This is homework for next Monday 27-3)