The document classifies triangles into six categories based on the lengths of their sides and size of their angles. Triangles are either equilateral with three equal sides and three 60 degree angles, isosceles with two equal sides, or scalene with no equal sides. Additionally, triangles can be right with one 90 degree angle, acute with all angles less than 90 degrees, or obtuse with one angle greater than 90 degrees. An equilateral triangle has all three angles congruent and equal sides.

1. Is a polygon with three sides and three vertices.

2. Classification of triangles according
to sides
 Equilateral Triangle – a triangle with three equal sides
 Isosceles Triangle – a triangle with two equal sides
 Scalene triangle - a triangle with no equal sides

3. CLASSIFICATION OF TRIANGLES
ACCORDING TO ANGLES
 Right triangle – a triangle with right angle
 Acute triangle – a triangle with three acute angles
 Obtuse triangle – a triangle with one obtuse angle
 Equilateral triangle – a triangle with all angles
congruent