MATEMATIČKI VIDEO NA DLANU (mathematics video lessons)   Video lessons without Words - Geometric Drawings and Constructions
		Croatian version
Here you can find videos that show geometric drawings and constructions on paper or in GeoGebra. Thanks to Rex Boggs, Rockhampton Grammar School, Australia (http://bit.ly/rexboggs) for help with the English translation.
Topics: >  Parallel Lines >  Perpendicular Lines >  Angles >  Dividing Line Segment >  Constructing Triangles >  Circumcircle and Inscribed Circle of the Triangle Construction >  Drawing / Sketching Geometric Bodies     >  Terms: drawing, construction and sketch

 

 

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Parallel Lines

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Parallel Lines - Drawing and Naming (using a triangle and ruler) How do you draw parallel lines and parallel line segments on the paper?
What is the symbol for "is parallel to"?
What is the symbol for "is not parallel to"?
Find the answers in this video.

 

Constructing Parallel Lines (using a straightedge and compass) Did you know that we can draw parallel lines using just a straightedge and a compass (without a set square)? In that case, we say that we construct parallel lines.
To learn how to do it, watch this video.
1st part of the video:
For given line a we construct line b which is parallel to the line a.
2nd part:
For given line c and external point T, we construct line d which goes through point T and is parallel to line c.

 

Drawing Parallel Lines in GeoGebra In this video you can see how to draw parallel lines and parallel line segments in GeoGebra (GGB) and how to write that they are parallel.

 

 

Perpendicular Lines

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Perpendicular Lines - Drawing and Naming (using a triangle and ruler) How do you draw perpendicular lines and perpendicular line segments on paper?
What is the symbol for "is perpendicular to"?
What is the symbol for "is not perpendicular to"?
Find the answers in this video.

 

Constructing Perpendicular Lines (using a straightedge and compass) Did you know that we can draw perpendicular lines using just a straightedge and a compass (without a set square)? In that case, we say that we construct perpendicular lines.
To learn how to do it, watch this video.
1st part of the video:
For given line a and point T on this line, we construct line b which is perpendicular to the line a and goes through point T.
2nd part:
For given line c and external point T, we construct line d which goes through point T and is perpendicular to line c.

 

Drawing Perpendicular Lines in GeoGebra In this video you can see how to draw perpendicular lines and perpendicular line segments in GeoGebra (GGB) and how to write that they are perpendicular.

 

 

Angles

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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 | Angle Bisector Construction 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° 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° 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° 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° 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° 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° 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.

 

 

Dividing Line Segment

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Constructing the Perpendicular Bisector of a Line Segment The perpendicular bisector of a line segment is the line which is perpendicular to a given line segment and which divides it into two equal line segments.
How to construct the perpendicular bisector of a line segment (by using just a straightedge and compass, without a triangle)?
Find the answer in this video.
Construction on paper.
Video without words.

 

Dividing Line Segments into Equal Parts - on Paper In this video you will learn how to divide a line segment into equal parts, without measuring.
Drawing on paper.

 

Dividing Line Segments into Equal Parts - in GeoGebra For given line segment and slider n (whose value we can change) we should divide the line segment into n equal parts.
How to do it, watch in this video.
Drawing in GeoGebra.

 

Dividing a Line Segment in a Given Ratio - on Paper In this video you will learn how to divide a line segment in a given ratio, without measuring.
Drawing on paper.

 

Dividing a Line Segment in a Given Ratio - in GeoGebra In this video you will learn how to divide a line segment in a given ratio, without measuring.
Drawing in GeoGebra.

 

 

Constructing Triangles

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Constructing triangles SSS - 1st part How to construct a triangle with all three sides given? Find the answer in this video.
Geometric construction with the transfer of side lengths using a compass.
If you are interested in the SSS construction where the side lengths are given in centimeters, look for the 2nd part of the video of the same name.
SSS = 'side-side-side'.
Construction on paper.
Video without words.

 

Constructing triangles SSS - 2nd part How to construct a triangle with all three sides given, in centimeters? Find the answer in this video.
If you are interested in SSS construction with the transfer of side lengths using a compass, look for part 1 of the video of the same name.
SSS = 'side-side-side'.
Construction on paper.
Video without words.

 

Constructing triangles SAS How to construct a triangle if the lengths of its two sides and the size of the angle between them are given? Find the answer in this video.
Geometric construction with the transfer of side lengths and angle sizes using a compass.
SAS is short for 'side-angle-side'.
Construction on paper.
Video without words.

 

Constructing triangles ASA How to construct a triangle if the length of one side and the size of the angles adjacent to that side are given? Find the answer in this video.
Geometric construction with the transfer of side lengths and angle sizes using a compass.
ASA is short for 'angle-side-angle'.
Construction on paper.
Video without words.

 

 

Circumcircle and Inscribed Circle of the Triangle Construction

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Circumcircle of a Triangle Construction | How to Draw a Circumcircle of a Triangle How to construct a circumcircle of a triangle?
Find the answer in this video.
Geometric construction using a ruler and a compass.
Construction on paper.
Video without words.

 

Inscribed Circle of a Triangle Construction | How to Draw the Inscribed Circle of a Triangle How to construct a inscribed circle of a triangle?
Find the answer in this video.
Geometric construction using a ruler and a compass.
Construction on paper.
Video without words.

 

 

Drawing / Sketching Geometric Bodies

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How to draw a cuboid | How to sketch a cuboid | Drawing a cuboid How to draw /shetch a cuboid? Find the answers in this video.

 

How to draw a cube | How to sketch a cube | Drawing a cube ¸ How to draw /shetch a cube? Find the answers in this video.

 

 

Explanations of the terms drawing, construction and sketch: top

Drawing When we draw (in geometry) then we are allowed to use a range of geometric tools such as a triangle, straightedge, ruler, compass and a protractor.

Construction When we construct, we are only allowed to use a compass and/or a straightedge. Measuring using a ruler or a triangle is not allowed. Transferring a distance or a length can be done with a compass.

Sketch To sketch means to draw without any geometrical equipment, using just a pencil. We can sketch when it's not important to have a precise drawing.

 

 

 

 

 

 

Background photo by stein egil liland