Formulas for area

Rectangle
1. Perimeter of rectangle = 2(Length+Breadth)
2. Area of rectangle = Length * Breadth

Square
1.Area of square = side²
2.Area of square = (1/2) diagonal²
3.Area of 4 walls of a room = 2(Length+Breadth)*Height

Triangle
1.Area of triangle = (1/2) * base * height
2.Area of triangle =

Where a,b,c are sides of triangle and s = (1/2)(a+b+c)
3.Area of an equilateral triangle = (√3/4) * (side)²

Parallelogram
Area of Parallelogram = base * height

Rhombus
Area of Rhombus = (1/2) * (Product of the diagonals)

Trapezium
Area of trapezium = (1/2) * (sum of parallel sides) * (distance between the parallel sides)

Circle
1.Circumference of the circle = 2 * pi * radius, pi=3.14
2. Area of the Circle = Pi * r²
3.Area of a sector = (Pi * radius² * angle ) /360
4. Area of semi circle = (1/2) * Area of circle
5.Circumference of a semi circle = (1/2) * Circumference of circle