Important Formulas: Triangles | Mathematics (Maths) Class 9 PDF Download

Important Formulas

Different Criterion for Congruence of the triangles

Some Important Points on Triangles

• Orthocenter: Point of intersection of the three altitude of the triangle
• Equilateral: Triangle whose all sides are equal and all angles are equal to 60º
• Median: A line Segment joining the corner of the triangle to the midpoint of the opposite side of the triangle
• Altitude: A line Segment from the corner of the triangle and perpendicular to the opposite side of the triangle
• Isosceles: A triangle whose two sides are equal
• Centroid: Point of intersection of the three median of the triangle is called the centroid of the triangle
• In center: All the angle bisector of the triangle passes through same point
• Circumcenter: The perpendicular bisector of the sides of the triangles passes through same point
• Scalene triangle: Triangle having no equal angles and noequal sides
• Right Triangle: Right triangle has one angle equal to 90º
•  Obtuse Triangle: One angle is obtuse angle while other two are acute angles
• Acute Triangle: All the angles are acute