Open the applet and move the armarm arm of the angle. Watch how the name of the angleangleangle changes depending on its size.

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Aplet geogebry: Katy i ich rodzaje. Poniżej znajduje się galeria ilustracji stanowiących alternatywę dla apletu.

Aplet geogebry: Katy i ich rodzaje. Poniżej znajduje się galeria ilustracji stanowiących alternatywę dla apletu.

Zasób interaktywny dostępny pod adresem https://zpe.gov.pl/a/DyuX7TVO1

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Rysunek kąta ostrego i podpis acute angle.

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Rysunek kąta rozwartego i podpis obtuse angle.

Sum up your observations:

• The angleangleangle greater than 0 and smaller than 90 degrees is called an acute angleacute angleacute angle.

• The angle with the measuremeasuremeasure of 90 degrees is called a right angleright angleright angle.

• The angleangleangle greater than 90 and smaller than 180 degrees is called an obtuse angleobtuse angleobtuse angle.

Draw in your notebooks:

• An right angleright angleright angle.

• Three acute angles.

• Three obtuse angles.

Answer the following questions:

• Is every acute angleacute angleacute angle smaller than the right angleright angleright angle?

• Is the measuremeasuremeasure of the obtuse angleobtuse angleobtuse angle smaller than the acute angleacute angleacute angle?

• Does an acute angle greater than 45° exist?

• Is the angleangleangle 20° greater than the 75° acute angleacute angleacute angle?

An extra task:

Using various sources of information, the literature or the Internet answer the following questions:

• What is the measuremeasuremeasure of the zero angle, the straight angleangleangle, the round angle? What do such angles look like?

• What angles are called convex angles? Give the examples.

• What angles are called concave ones? Give the examples.

You have learned the notion of the angleangleangle:

The angleangleangle is a part of a planeplaneplane cut out by two half‑lines with a common beginning. These half- lines are called the arms of the angleangleangle, the beginning is called the vertexvertex vertex of an angle.

Remember, there are three main types of the angles:

• acute angles from 0 to 90 degrees,

• right angles of 90 degrees,

• obtuse angles from 90 to 180 degrees.

Draw the acute, the right, the obtuse angles in your notebook. Identify the angles and write down their types.

Describe in English the elements of the angle construction and the angle types.