The document defines and describes different types of triangles, including equilateral, isosceles, right-angled, acute, obtuse, scalene, acute scalene, and obtuse scalene triangles. Key characteristics are provided for each type, such as equilateral triangles having three equal sides, isosceles triangles having two equal sides, right triangles having one 90 degree angle, and obtuse triangles having one angle greater than 90 degrees. Examples and illustrations are also included to explain the different triangle types.