## RS Aggarwal Class 6 Math Fifteenth Chapter Polygons Exercise 15 Solution

## EXERCISE 15

### Some Basic Concepts

**STRAIGHT LINE:** *We know that by moving a pencil along the straight edge of a ruler, we get a straight line.*

**CURVE:** *By moving a pencil along a curved edge, we get a curve.*

**CLOSED FIGURE:** *A figure which begins and ends at the same point is called a closed figure.*

**OPEN FIGURE:** *A figure which does not end at the straight point is called an open figure.*

**SIMPLE CLOSED FIGURE :**

*A closed figure which does not intersect itself is called a simple closed figure.*

**POLYGONS:** *A simple closed figure formed of three or more line segments is called a polygon.*

**SIDES:** *The line segments forming a polygon are called its sides.*

**VERTICES:** *The meeting point of a pair of sides of a polygon is called its vertex.*

**ADJACENT SIDES:** *Any two sides of a polygon having a common end point are called its adjacent sides.*

**DIAGONALS:** *A line segment joining two non-adjacent vertices of a polygon is called its diagonal.*

**TRIANGLE***: A polygon of 3 sides is called a triangle.*

**QUADRILATERAL:** *A polygon of 4 sides is called a quadrilateral.*

**PENTAGON:** *A polygon of 5 sides is called a pentagon*.

**HEXAGON:** *A polygon of 6 sides is called a hexagon.*

**HEPTAGON:** *A polygon of 7 sides is called a heptagon.*

**OCTAGON:** *A polygon of 8 sides is called an octagon.*

**(1) Which of the following are simple closed figures?**

**(2) Which of the following are polygons?**

**(3) Fill in the blanks:**

(i) A polygon is a simple closed figure formed by more than __two__ line segments.

(ii) A polygon formed by three line segments is called a __triangle__.

(iii) A polygon formed by four line segments is called a __quadrilateral__.

(iv) A triangle has __3__ sides and __3__ angles.

(v) A quadrilateral has __4__ sides and __4__ angles.

(vi) A figure which ends at the starting point is called a __closed figure__.