Notes

Heron’s Formula * Heron’s formula is used to determine the area of a triangle, when the lengths of the three sides are known. * Heron’s formula to find the area of a triangle is \sqrt{s (s - a)( s - b)( s - c)} , Where,  a, b and c are the lengths of the ... Read more

Basic Constructions Angle bisector: An angle bisector is ray, which divides an angle into two equal parts. Perpendicular bisector: A perpendicular bisector is a line, which divides a given line segment into two equal halves and is also perpendicular to the line segment.

Basic Concept of A Circle * The collection of all the points in a plane that are at equal distance from a given fixed point in the plane is called a circle. * A line segment joining the centre of a circle with any point on its circumference is called the radius of a circle. ... Read more

Areas of Parallelograms * Area of a parallelogram is equal to the product of its base and corresponding height. * The diagonal of a parallelogram bisect each other. * A diagonal of the parallelogram divides it into two congruent triangles. * Opposite sides and angles of a parallelogram are equal. * Two congruent figures have ... Read more

Quadrilaterals And Its Types Quadrilateral: A closed figure having four sides, four angles and four vertices. Parallelogram: A quadrilateral in which, opposite sides are parallel and equal, opposite angles are equal, the diagonals bisects each other, each diagonal divides parallelogram into two congruent triangles and adjacent angles are supplementary. Square:  A parallelogram in which, all ... Read more

Congruence of Triangles * Two triangles are congruent, if the sides and angles one triangle are equal to corresponding sides and angles of the other triangle. * There is one-to-one correspondence between the vertices f two congruent triangles ABC and XYZ such that A ↔ X, B ↔ Y and C ↔ Z. * Two ... Read more

Introduction to Lines and Angles Line Segment: A line with two end Points Ray: a line with one end point. Collinear points: If three or more points lie on the same line they are collinear. Angle: The figure formed by two rays having a common end point. Acute Angle: An angle whose measure is more ... Read more

Introduction to Euclid’s Geometry Euclid’s Definitions Definition 1: A point is that which has no part. Definition 2: A line is breathless length. Definition 3: The ends of a line are points. Definition 4: A straight line is a line which lies evenly with the points on itself. Definition 5: A surface is that which ... Read more