1. Geometrical Construction
Engineering Graphics
TA 101

2. 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.

3. Quadrilaterals

4. Polygons:
3. Polygons: Regular or irregular; when all sides are equal, it is a regular polygon, otherwise irregular.
Pentagon Sides
Hexagon Sides
heptagon Sides Octagon Sides
Nonagon Sides Decagon Sides

5. To Bisect a line, an arc

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

7. To divide a given line into No. of equal parts

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