CHAPTER 10POLYGONS

10.1. PolygonsA polygon: A two dimensional shape that is enclosed by straight lines on all its sides.The number of vertices = the number of sides.The number of diagonals = n (n 3), where n is the number of sides

For example: ABCD is a polygon with four sides, AB, BC, CD and DA.The vertices A, B, C and D are written in capital letters.Diagonals: lines that join two non-adjacent vertices, AC and BD.ADCBsidevertexdiagonal

A polygon is named according to the number of sides.

10.2. SymmetryA shape is said to have a line of symmetry if it is can be divided equally so that one half overlaps exactly onto the other.The line of symmetry is also known as the axis of symmetry.E.g.: line/axis of symmetry

10.3. TrianglesA triangle: A polygon which has three sides.An equilateral triangle has 3 lines of symmetry.

An isosceles triangle has 1 line of symmetry.

Types of triangles

The sum of the angles of a triangle = 180

10.4. Quadrilaterals: Polygons with 4 sides

The sum of the angles of a quadrilateral = 360

PREPARED BY:NORASHIKIN BINTI MOHAMAD