Area of a Trapezium and a Polygon — Formula Sheet

Perimeter = a + b + c

s = (a + b + c)/2

Area = √(s(s-a)(s-b)(s-c))

Area = (1/2) × base × height

base = (2 × area)/height

Perimeter of rectangle = 2(l+b)

Area of rectangle = l × b

Diagonal of rectangle = √(l² + b²)

Perimeter of square = 4 × side

Area of square = side²

Area of trapezium = (1/2) × (a+b) × h

h = (2 × area)/(a+b)

a+b = (2 × area)/h

1 m = 100 cm.

Semi-perimeter s = (a+b+c)/2.

Rectangle perimeter = 2(l+b).

Rectangle area = l × b.

Rectangle diagonal = √(l²+b²).

The area of an equilateral triangle of side a is (√3/4)a².

Perimeter of a rectangle is 2(l+b), area is l×b, and diagonal is √(l²+b²).

Perimeter of a square is 4×side, area is side², and diagonal is side√2.