Perpendicular Lines with the Aid of a Pair of Set Squares

Par de Esquadros - Triangle - Juego de Escuadras

perpendicular lines with the aid of a pair of triangle or set square

Perpendicular straight lines when drawing, or 90º, with the help of a pair of triangle or set square

The set sqaures are used as design tools for tracing and solving geometry problems. It is possible to draw various geometric entities with the aid of a pair of set squares, this animation is part of the educacional program O Desenho Geométrico em Multimídia

The pair of supports or set square consists of a square with a right angle and two angles of 45° and the other with a right angle, one of 30º and another of 60º. In it, the hypotenuse of the triangle with angles 45° is consistent with the longest side of the triangle with angles of 30° and 60°. Using media without chamfer or graduation is recommended.

Technical design
Drawing perpendicular lines with the help of a pair of triangles or set square


  1. Use a square to draw the first line;
  2. Without moving, hold the second square on one of its sides;
  3. Slide the first square using the second reference;
  4. Change the position of the second square supporting the 90° angle side;
  5. Position the square and draw a line perpendicular to the first.


Eduardo Stefanelli

Engenheiro por profissão, professor por vocação