Geometry for Elementary School/Our tools: Ruler and compass

Construction Our Tools: Ruler and compasses Constructing equilateral triangle Introduction thumb|300px|center|This is a picture of a pair of compasses and a ruler. How to draw a line thumb|300px|left|Using a ruler (based on Book I, Postulate 1), we can draw a segment of a straight line. We will use the notation for the line segment the starts at A and ends at B. Note that we don't care about the segment direction and therefore is the same as . thumb|300px|center|Line segment thumb|300px|center|Line segment How to draw a circle Using the compass (based on Book I, Postulate 3). We use the notation for the circle whose centre is the point A and its radius length equals that of the segment . 300px|center Note that in other sources, such as Euclid's Elements, a circle is described by any 3 points on its circumference, ABC. The center-radius notation was chosen because of its suitability for constructing circles with a ruler and a compass. it:Geometria per scuola elementare/I nostri strumenti: Riga e compasso pl:Geometria dla szkoły podstawowej/Przyrządy: cyrkiel i linijka pt:Matemática elementar/Geometria plana/Construções geométricas usando régua e compasso ru:Геометрия для средней школы/Наши инструменты: Линейка и циркуль