Introduction, Formulae to perimeter of a square, rectangle and triangle. with solved examples.

1. Perimeter
Rectangles, Squares, and
Triangles

2. What is Perimeter?
Perimeter isthedistancearound atwo
dimensional shape, or themeasurement of
thedistancearound something; thelength
of theboundary.

3. What is a rectangle?
A rectangle has:
 4 sides
 4 square corners or right
angles
 Opposite sides are of equal
lengths
 Opposite sides are directly
across from each other

4. To find the perimeter of a
rectangle:
6 cms
9 cms
Use the formula
P= 2 (length + breadth)P= 2 (length + breadth)
If length of a rectangle is 9 cms and its breadth is 6 cms.
Find the perimeter of the rectangle.
Sol: P = 2(l+b)
= 2(9+6)
= 2(15)
= 30 cms

5. What is a square?
A square has:
 4 equal sides
 4 right angles

6. To find the perimeter of a square:
Use the formula:
12 cms
P = 4 x sideP = 4 x side
Find the perimeter of a square whose side is 12
cms.
Sol: P = 4 x side
= 4 x 12
= 48 cms

7. What is a triangle?
 A triangle has 3 sides.
All triangles may not look the same,
but they all have 3 sides.

8. To find the perimeter of a
triangle:
Use the formula:6 cms 9 cms
5 cms
P = a + b + cP = a + b + c
Find the perimeter of a triangle whose sides are
6cms, 9cms and 5cms.
Sol: P = a + b + c
= 6 + 9 + 5
= 15 + 5
= 20 cms

9.  A triangular plot of land has sides 60m,
25m and 30m. It is to be fenced with 4
rounds of wire. What is the total length
of the wire required for the pupose?

10.  A triangular plot of land has sides 60m,
25m and 30m. It is to be fenced with 4
rounds of wire. What is the total length
of the wire required for the pupose?