Congruent Figures In our daily life we see many congruent objects like as,  (i) Two 2 Rupees, 5 Rupees, or 10 Rupees coins. (ii) Two text books of mathematics of same class.  Two figures or objects are called congruent, when one object cover the other completely and exactly. This means that two books or coins […]

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 Convex Polygons: Definition – Examples and Properties   All polygons is either convex or concave. A polygon will be convex or concave, it depends on the measure of their angles. If the measures of all interior angles is less 1800 than the polygon is convex, otherwise the polygon is concave.                 […]

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Converse of Pythagorean Theorem  In this section we are going to see the converse of Pythagorean theorem. We know the Pythagorean theorem applies to right triangles and states that,  The square of the length of the hypotenuse, equals the sum of the squares of the lengths of the other two sides.  (hypotenuse)2 = (Base)2+(Perpendicular)2     […]

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  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 […]

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Theorem – The line segment joining the mid-points of two sides of a triangle is parallel to the third side. Given: A triangle △ABC, in which D and E are mid points of sides AB and AC respectively. DE is joined. To prove: Line joining the mid points D and E (DE) is parallel to the third line […]

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 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. […]

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Perimeter of shapes Definition:  The distance that surrounds a two dimensional shape is known as “Perimeter.”   Simply, we can say that ‘The Perimeter is the length of the outline of a shape.  In the below figure if we start measure from the point A and move along the line segments and reach again the point A.We have […]

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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 […]

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Theorem The perpendicular from the center of a circle to a chord bisects the chord. Given: A circle with center O, AB is chord of a circle and OC perpendicular from the center to the chord  AB. i.e.    OC ⊥ AB  therefore  ∠OCA and ∠OCB Both angles are 900.   To prove: AC = CB (C is the mid point of chord AB)    […]

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Exterior Angle of a Triangle If any side of a triangle is extended then the exterior angle of triangle is equal to the sum of its interior opposite angles. Given : A △ABC, side BC of △ABC is extended, ∠ACD is an exterior angle. To Prove : The sum of measure of exterior angle of triangle is equal to the sum […]

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