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 – 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 […]
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 →Theorem – Alternate Interior Angles are Equal If a transversal intersects two parallel lines, then each pair of alternate interior angles are equal. Given: Two parallel Lines AB and CD, and PS be transversal intersecting AB at Q and CD at R. To Prove: Each pair of alternate interior angles are equal. i.e. ∠BQR = ∠CRQ and ∠AQR = ∠QRD […]
Read More →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 […]
Read More →Definition, Properties, Examples – Cyclic Quadrilaterals What is a Cyclic Quadrilateral A cyclic quadrilateral is a four sided polygon that is inscribed in a circle. The vertices are said concyclic. The center of the circle is called circumcenter and radius of the circle is called circumradius. Definition: A Cyclic Quadrilateral is a quadrilateral, whose all four vertices […]
Read More →Triangle – Definition and Properties The origin of term “Triangle” from latin word tri (“Three”) and angulus means (“angles”). A “Triangle” is a simple closed curve or a three sided polygon. A triangle has three angles and three sides and three vertices. It is one of the basic shape in geometry. In Euclidean geometry any non-collinear, three points, determine a unique triangle. The triangle […]
Read More →What is an Acute Triangle: Definition, Formula and Properties In geometry, a triangle is a polygon with three sides, three vertices and three interior angles. In other words a triangle is a closed two dimensional plane figure with three sides and three angles. Triangles are classified on the basis of their sides and angles. There […]
Read More →Quadrilaterals – Definition – Properties The word “quadrilateral” has two Latin words quadri, a variant of four and latus meaning is “side”. What is a quadrilateral A quadrilateral is a polygon, with four edges or sides and four vertex or corners. Just like as a triangle is 3 sides polygon, […]
Read More →Properties of a Rectangle A rectangle is a two dimensional four sided polygon(quadrilateral), in which the opposite sides are equal and parallel to each other and all four angles are right angles. In figure ABCD is a rectangle. Properties of a Rectangle A rectangle is a quadrilateral. 1. Each interior angle is a right angle. 2. […]
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