What Have We Discussed ?

1. Perimeter is the distance covered along the boundary forming a closedopen figure when we go round the figure time(s).

2. (a) Perimeter of a rectangle with length "m" and breadth "n" = 2×(m+n)m×n

(b) Perimeter of a square with side "s" = 4×ss2

(c) Perimeter of an equilateral triangle with side "l" = 3×ll2

3. Figures in which all sides and angles are are called regular closed figures.

4. The amount of surface enclosed by a closed figure is called its .

5. To calculate the area of a figure using a squared paper, the following conventions are adopted:

(a) Ignore portions of the area that are than half a square.

(b) If more than half a square is in a region, count it as square.

(c) If exactly half the square is counted, take its area as sq units.

6. (a) Area of a rectangle with length "m" and breadth "n" = m×n2mn

(b) Area of a square with side "s" = s×s2(s×s)