Quadrilaterals and Polygons

Quadrilaterals and Polygons

Quadrilateral:

Sum of interior angles = 360 deg

Parallelogram:

Opposite sides equal and parallel
Opposite angles equal
Diagonals bisect each other
Area = base * height

Rectangle:

Area = l*b
Diagonal = sqrt(l^2 + b^2)

Square:

Area = a^2
Diagonal = a*sqrt(2)

Rhombus:

Area = 1/2 * d1 * d2
Diagonals are perpendicular bisectors

Trapezium:

Area = 1/2 * (sum of parallel sides) * height

Regular polygon:

Sum of interior angles = (n-2)*180 deg
Each interior angle = (n-2)*180/n deg
Each exterior angle = 360/n deg
Number of diagonals = n(n-3)/2