This presentation discusses the properties of triangles. It begins with an introduction that defines a triangle as a closed figure with three line segments and three vertices. It then classifies triangles based on their sides as equilateral, isosceles, or scalene triangles. Additional classifications are made based on angles, including right-angled, acute-angled, and obtuse-angled triangles. The presentation describes key geometric elements of triangles, such as medians that connect vertices to midpoints of opposite sides, altitudes that are perpendicular lines from vertices to opposite sides, and the property that exterior angles equal the sum of their two interior opposite angles.