MENSURATION

In mensuration we often have to deal with the problem of finding the areas of plane figures.

Some Elementary Definitions  :

1. Rectangle :  A quadrilateral with opposite sides equal and all the four angles equal to 90 degree.
2. Square :  A quadrilateral with all sides equal and all the four angles equal to 90 degree.
3. Parallelogram :   A quadrilateral with opposite sides parallel and equal.
4. Rhombus : A Parallelogram with all four sides equal.
5. Trapezium :  A quadrilateral with any one  pair of opposite sides parallel.
6. Right angled triangle :  A triangle with one angle equal to 90 degree.
7. Isoceles triangle :  A triangle with any two sides equal.
8. Equilateral triangle :  A triangle with all sides equal.
9. Perimeter :  The length of the outer boundry of the geometrical figure.
10. Arc of a Circle :  A portion of the perimeter of the circle.
11. Sector of a Circle :  The area covered between an arc, the center and two radii of the circle.