Download 2D Figures

Chapter 5 – Introduction of Geometry
(2-D Figures)
Polygon
– plane figures enclosed by 3 or more sides of straight lines.
- named according the number sides.
Name
Triangle (3)
Quadrilateral (4)
Pentagon (5)
Hexagon (6)
Diagram
Note: Number in ( ) represents the number of sides of the polygon
If all the sides and angles of a polygon are equal, it called a regular polygon.
Name
Sqaure (4)
Regular pentagon
(5)
Regular Hexagon
(6)
Regular Heptagon
(7)
Diagram
Other polygons: Octagon, Nonagon and Decagon.
1. Triangles
(a) According to sides
Triangle without any equal sides Triangle with three equal sides
Triangle with two sides
(b) According to angles
Triangle with 3 acute angles
Triangle with an obtuse angle
Triangle with a right angle
2. Quadrilaterals
Square
Rectangle
Parallelogram
Trapezium
Rhombus
Kite
Questions:
Which of the following statements are correct? Why?
(i)
Square are also rectangles.
(ii)
Squares are also rhombuses.
(iii) Squares and rhombuses are also kites.
(iv) Squares, rectangles and rhombuses are also parallelograms.