Geometrical Construction Engineering Graphics TA 101

Important Geometrical Terms 1. Triangles – Equilateral, Isosceles and scalene. ( A Scalene triangle has three unequal sides) 2. Quadrilaterals Square – all sides equal and all angles right angles. Rectangle or Oblong – opposite sides equal and all angles right angles Rhombus – all sides equal, but angles are not right angles. Rhomboid – opposite sides equal and parallel, but angles are not right angles. Trapezoid – only two sides parallel Trapezium – no sides parallel, but may have two of its sides equal. When two of the sides are equal, it is called a trapezion or kite.

Quadrilaterals

Polygons: 3. Polygons: Regular or irregular; when all sides are equal, it is a regular polygon, otherwise irregular. Pentagon - 5 Sides Hexagon - 6 Sides heptagon - 7 Sides Octagon - 8 Sides Nonagon - 9 Sides Decagon - 10 Sides

To Bisect a line, an arc

To Bisect an angle Acute (<90) obtuse (>90) Right angle (=90)

To divide a given line into No. of equal parts

To draw a polygon when radius of circle is given Inscribed in a circle Circumscribe about a circle