Rhombus – Definition – Properties Definition: A rhombus is a quadrilateral (closed shape, plane figure) with four straight sides that are equal length also opposite sides are parallel and opposite angles are equal. A rhombuses is a type of parallelogram. All rhombuses are parallelograms, but not all parallelograms are rhombuses.  All squares are rhombuses, but not all […]

Read More →

Interior & Exterior angle of a polygon  In this lesson we will learn the, (1) Solutions of problems on interior and exterior angles of a polygon.  Example 1: Find the sum of all interior angles in a regular triangle (3-sided). Solution: Step 1: Write the formula Sum of interior angles of a polygon = (n-2) […]

Read More →

Concave Polygons: Definition – Examples & Properties   All polygons is either convex or concave. A polygon will be convex or concave, it depends on the measure of their angles. What is a Concave Polygon? A concave polygon have at least four sides, and concave polygon is just opposite of a convex polygon. If the measures […]

Read More →

Law of Tangents – Definition – Formula – Proof and Examples In trigonometry, the law of tangents describes the relationship between the sum and difference of sides of a right triangle and tangents of half of the sum and difference of the angles opposite to the sides. Formulas for law of tangents The law of tangents […]

Read More →

  Diagonals of Polygon’s In geometry, a line segment joining two vertices of a polygon or polyhedron, when those vertices are not adjacent is known as Diagonal.  Diagonals of Polygon’s A polygon’s diagonal’s are line segments, that joining from one corner to another corner. Formula for number of diagonals = n(n-3)/2 where n is number of sides or […]

Read More →

Polygon – Interior and Exterior & Central Angles Interior angle of a regular polygon A regular polygon has all the interior angles same in measure, and all interior angles of polygon formed by each pair of adjacent sides. When a polygon has n sides n vertices and n interior angles. Interior angle = 1800 – Central angle […]

Read More →

 Theorem : In a parallelogram, opposite angles are equal.  Given: A parallelogram ABCD,  opposite sides of parallelogram are                         side AB and side DC                         side AD and side BC. To prove: Opposite angles of parallelogram are equal. […]

Read More →

History of Coordinate Geometry The Cartesian system or the rectangular coordinate system was invented in seventeenth century by Rene Descartes, the great French philosopher and mathematician. The coordinate system is also called the Cartesian system. Geometry was well developed to describe the dimension of an object, but it does not describe the position of an object. So, to […]

Read More →

SSS, SAS, ASA, AAS and RHS – Congruence of Triangles  In geometry we see that, if two line segments are are same in length, they are congruent, and if two angles are same in measure they are also congruent,.Simply, we can say congruent means an object and its mirror image. Congruence Triangles A triangle is a polygon with […]

Read More →