Here Some Basic Formulas/Rules Are given below :-
Area of a rectangle = (Length x Breadth).
so Length =
and Breadth =
Perimeter of a rectangle = 2 (Length + Breadth).
Area of a square = (side)2 = 1/2(diagonal)2.
Area of 4 walls of a room = 2 (Length + Breadth) x Height.
Area of a triangle = 1/2 X Base X Height.
Area of a triangle = √s (s - a) (s - b) (s - c) where a, b, c are the sides of the triangle and s = 1/2 (a + b + c).
Area of an equilateral triangle = √3/4 X (side)2
Radius of incircle of an equilateral triangle of side a = a/2√3
Radius of circumcircle of an equilateral triangle of side a = a/√3
Radius of incircle of a triangle of area Δ and semi-perimeter s = Δ/s
Area of a parallelogram = (Base x Height).
Area of a rhombus = 1/2 X (Product of diagonals).
Area of a trapezium = 1/2 X (sum of parallel sides) X distance between them.
Area of a circle = πR2, where R is the radius
Circumference of a circle = 2πR.
Length of an arc = = 2πRo/360 where o is the central angle.
Area of a sector = = 1/2 (arc X R) = πR2o /360
Area of a semi-circle = πR2/2
Circumference of a semi-circle = πR.
FUNDAMENTAL CONCEPTS :-
Results on Triangles :
Results on Quadrilaterals :