Page 105 - classs 6 a_Neat

CURVE By moving a pencil along a curved edge (like that of a coin), we get a curve. ADJACENT SIDES Any two sides of a polygon having a common end point are called its
adjacent sides.

Thus, (AB, BC), (BC, CD), (CD, DA) and (DA. AB) are four pairs of adjacent sides in the given
polygon ABCD.

Here (A, B), (B, C). (C, D) and (D, A) are the pairs of adjacent vertices.
CLOSED FIGURES Afigure which begins and ends at the same point is called a closed figure.
DIAGONALS A line segment joining two non-adjacent vertices of a polygon ts called its diagonal.
Each of the figures given below is a closed figure.
Thus, AC and BD are the diagonals of the given polygon ABCD.

TRIANGLE A polygon of 3 sides ts called a triangle.

QUADRILATERAL A polygon of 4 sides ts called a quadrilateral.

PENTAGON A polygon of 5 sides ts called a pentagon.

HEXAGON A polygon of 6 sides ts called a hexagon.

OPEN FIGURES Afigure which does not end at the starting point is called an open figure. HEPTAGON A polygon of 7 sides ts called a heptagon.
Each of the figures given below is an open figure.
OCTAGON A polygon of 8 sides ts called an octagon

A triangle has 3 sides, 3 angles and 3 vertices.
SIMPLE CLOSED FIGURES A closed figure which does not intersect itself ts called a simple closed A quadrilateral has 4 sides, 4 angles and 4 vertices.
figure. A pentagon has 5 sides, 5 angles and 5 vertices.
A hexagon has 6 sides, 6 angles and 6 vertices.
Thus, out of the examples given above for closed figures (i), (ii) and (iii) are simple closed figures. A heptagon has 7 sides, 7 angles and 7 vertices.
An octagon has 8 sides, 8 angles and 8 vertices.
POLYGONS A simple closedfigureformed of three or more line segments ts called a polygon.
Line Line Segment Ray
SIDES, VERTICES AND DIAGONALS OF A POLYGON A line has no definite
1. length. A line segment has a definite A ray has no definite length.
SIDES The line segments forming a polygon are called its sides. length.

In the given figure, ABCD is a polygon in which AB, BC, CD and DA A line has no end A line segment has two end
are its four sides. 2. point. points. A ray has one end point.

VERTICES The meeting point of a pair of sides of a polygon ts called its vertex. A line has no thick-
3. ness. A line segment has no thickness. A ray has no thickness.
Thus, A, B, C, Dare the four vertices of the given polygon ABCD. VERTICES The meeting point of a pair
of sides of a polygon ts called its vertex. The line AB is repre- The line segment AB is The ray AB is represented
4. sented by AB. represented by AB. by AB
Thus, A, B, C, Dare the four vertices of the given polygon ABCD.