what you'll learn...
overview
In this page, overview of the geometrical instruments is provided • graduated ruler or scale • compass • protractor • divider • set-squares or set-triangles
ruler / scale
The geometrical instrument in the figure is called a "ruler".
A "ruler" is used to construct a straight line.
The marks or graduations on the ruler show the length measure in millimeter and centimeter.
Other than to construct straight lines, A "ruler" is used to measure a line-segment.
The word "ruler" means: a straight stick.
The word "ruler" is derived from a root word meaning straight stick.
The phrase "graduated ruler" means: a straight stick with grade of length measure marked on them.
Note: A ruler is also referred with the name "scale".
summary
Graduated Ruler or scale : A ruler is a straight stick with grade of length measure marked. It is used to construct straight lines and measure a line-segment.
compass
The geometrical instrument in the figure is called a "compass".
A "compass" is used to construct an arc of given radius. The arc has points that are in equal distance from the center point.
The word "compass" is (possibly) from root words "com+pace" meaning "together+take-steps".
summary
Compass : An instrument to measure a length and construct an arc of a given radius.
divider
The geometrical instrument in the figure is called a "divider".
A "divider" is used to measure the length between two points.
summary
Divider : is a geometrical instrument which is used to measure the length between two points.
protractor
The geometrical instrument in the figure is called a "protractor".
A "protractor" is used to mark an angle of given measure.
The word "Protractor" is from root words "protract+tor", which means "draw-out or lengthen a line".
summary
Protractor : is a geometrical instrument which is used to mark a measure of an angle.
set sequares
The geometrical instrument in the figure is called a "set squares" or a "set triangles".
The name "set squares" calls by the two 90∘90∘ angles provided by the instruments.
The name "set triangles" calls by the shape of the two pieces. Both names are used.
A "set squares" is used • to construct perpendicular and parallel lines
• to measure standard angles 90∘90∘, 30∘30∘, 45∘45∘, 60∘60∘ etc.
summary
Set Squares or Set Triangles : is a pair of triangular pieces used to construct parallel lines or to measure the standard angles 90∘90∘, 30∘30∘, 45∘45∘, 60∘60∘ etc.
summary
Graduated Ruler or scale : A ruler is a straight stick with grade of length measure marked. It is used to construct straight lines and measure a line-segment.
Compass : An instrument to measure a length and construct an arc of a given radius.
Divider : is a geometrical instrument which is used to measure the length between two points.
Protractor : is a geometrical instrument which is used to mark a measure of an angle.
Set Squares or Set Triangles : is a pair of triangular pieces used to construct parallel lines or to measure the standard angles 90∘90∘, 30∘30∘, 45∘45∘, 60∘60∘ etc.