Page 217 - New Medley 5 Semester 1

Observe the following figures:

3 cm
1. 2. 6 m 3. 30 cm 20 cm

4 cm 5 cm 3 m 5 m 50 cm 30 cm

4 m 50 cm

Perimeter = 3 cm + 4 cm + 5 cm = 12 cm

Perimeter = 3 m + 4 m + 5 m + 6 m = 18 m

Perimeter = 30 cm + 20 cm + 30 cm + 50 cm + 50 cm = 180 cm

Perimeter of a Rectangle

A rectangle is a special type of the quadrilateral
b
whose opposite sides are equal of length.

\ Perimeter (P) of a rectangle l

= Length + Breadth + Length + Breadth

= l + b + l + b = 2l + 2b = 2(l + b)

Also note that if the two out of three l, b and P are given, we can find
the third.

P P
As P = 2(l + b), so l = – b and b = – l
2 2

Perimeter of a Square

As we know the square has all its sides equal in length. a

\ Perimeter (P) of a square = Side + Side + Side + Side
a a
= a + a + a + a = 4a or 4(Side)

Perimeter ()P
That is, side (a) = a
4

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