◆Definition of a polygon:-    A polygon is any 2-dimensional shape formed with straight lines, such that triangles quadrilaterals Pentagons and hexagons etc.     ◆Definition of A Triangle :-    A three sided polygon is called triangle.   ◆Definition of A Scalene Triangle :-   A triangle having three unequal sides is called scalene triangle.  ◆Definition of A Isosceles Triangle:-  A triangle having any two sides equal is called Isosceles triangle.  ◆Definition of A Equilateral Triangle :-   A triangle having all sides equal is called equilateral triangle.  ◆Definition of A Acute Angled Triangle:-   A triangle having all the three acute angles is acute angle is called acute angled triangle.  ◆Definition of A Obtuse angled triangle :-   A triangle having any one Obtuse angle is called obtuse angled triangle.   ◆Definition of A Right angled triangle :-   A triangle having one angle as right angle is called right angled triangle....