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Some names of the polygons are as follows:

Polygon Number of Sides Name of the Polygon

3 Triangle

4 Quadrilateral

5 Pentagon

6 Hexagon

7 Heptagon

8 Octagon

9 Nonagon

10 Decagon

Math Insight
Š Polygons are closed plane figures made up of only line segments which do not cross each other.
Š Each side of the polygon intersects exactly two other sides at the end points only.
Š No two sides cross each other.

Polygons that have equal sides are called regular polygons.
A regular triangle is a triangle in which all three sides are of equal length.
It is also called an equilateral triangle. Equilateral triangles have equal

angles which are acute angles. So, it is also called an acute-angled triangle.
Let us take two cutouts of equilateral triangles. Arrange them as shown
here.

They form a rhombus. A rhombus is a shape with four equal sides.
Let us take the rhombus shape formed by two equilateral triangles and
divide the triangles into halves as shown here. So, it has been divided into

four triangles.
We can see that each new triangle formed has sides of different lengths.
It is called a scalene triangle.

Also, this triangle has a right angle. So, it is also called a right-angled
triangle.

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