Angles

ANGLES
Definition: A shape, formed by two lines or rays diverging from a common point (the vertex).
Parts: vertex, legs, interior, exterior.

A triangle has three vertex

Animation.

USING A PROTACTOR
To measure angles
Animation. The animated diagram shows how to use a protractor to measure angles. It shows how to measure two angles that are vertical (=opposite) angles and so should be equal in measure.

• Step-by-step instruction sheet.

To draw angles
Animation. This shows how to use a protractor to draw an angle - 42° in this example.

• Step-by-step instruction sheet.

COPYING AN ANGLE

This page shows how to copy an angle. Given an angle formed by two lines with a common vertex, this animation shows how to construct another angle from it that has the same angle measure using a compass and straightedge or ruler.

• Step-by-step instruction sheet.

ADDING UP ANGLES (in your notebooks)
SUBTRACTING ANGLES (in your notebooks)

BISECT AN ANGLE

To bisect an angle means that we divide the angle into two equal parts without actually measuring the angle. How to bisect an angle with compass and straightedge or ruler animation.

• Step-by-step instruction sheet.

CONSTRUCT ANGLES 30º-45º-60º-90º

Construct a 30 degree angle
Construct a 45 degree angle
Construct a 60 degree angle
Construct a 90 degree angle

Using a protactor

• Try it yourself. Measuring an angle.
• Interactive activity to measure angles. Click "Mostrar transportador" and measure the angles. Recurso educativo del INTEF.
• Try it yourself. Drawing an angle.

Copying an angle

• Try it yourself. Copying an angle.

Bisect an angle

• Try it yourself. Bisecting an angle.

Constructing angles 30º-45º-60º-90º

• printable worksheet - 30º
• printable worksheet - 45º
• printable worksheet - 60º
• printable worksheet - 90º