Thanks to Rex Boggs, Rockhampton Grammar School, Australia (http://bit.ly/rexboggs) for help with the English translation.

Duplicating an Angle (Copying an Angle)

For a given angle, how do you construct an angle with the same
measure using just a straightedge and compass (without a protractor)?
Find the answer in this video.
Duplicating (copying) angles on paper.

Bisecting an Angle

The angle bisector is a line passing through the vertex of the angle
that cuts it into two equal smaller angles.
How to construct the angle bisector (by using just a straightedge and
compass, without a protractor)?
Find the answer in this video.
Construction on paper.

Constructing an Angle of 60 degrees

How to construct an angle of 60° (using just a straightedge and
compass, without a protractor)?
Find the answer in this video.
Construction on paper.

Constructing an Angle of 30 degrees

How to construct an angle of 30° (using just a straightedge and compass, without a protractor)?
Find the answer in this video.
Construction on paper.

Constructing an Angle of 120 degrees

How to construct an angle of 120° (using just a straightedge and
compass, without a protractor)?
Find the answer in this video.
Construction on paper.

Constructing an Angle of 90 degrees

How to construct an angle of 90° (using just a straightedge and
compass, without a protractor)?
Find the answer in this video.
Construction on paper.

Constructing an Angle of 45 degrees

How to construct an angle of 45° (using just a straightedge and
compass, without a protractor)?
Find the answer in this video.
Construction on paper.

Constructing an Angle of 75 degrees

How to construct an angle of 75° (using just a straightedge and
compass, without a protractor)?
Find the answer in this video.
Construction on paper.