This document discusses calculating the perimeter of simple 2D shapes like rectangles and squares. It defines perimeter as the total distance around the outside of a 2D shape. It provides the formulas for calculating the perimeter of a rectangle, which is the sum of the lengths of all its sides, and gives an example of calculating the perimeter of a rectangle that is 5 cm in length and 3 cm in breadth. The document also discusses calculating the perimeter of overlapping similar rectangles by adding up the lengths of all the sides.

1. Measurement
Perimeter
What will we learn today?
• calculation of the perimeter of
∗ rectilinear figure
∗ rectangle
∗ square

2. What is Perimeter?
The perimeter is the
total distance around the
outside of a 2D shape.

3. Let’s recall some concepts.
Length is the longest dimension of an object.
Breadth is the extent or measure of how broad
or wide something is.
Breadth 3cm
Length
5cm

4. Perimeter of Simple Shapes
There are special formulas for certain shapes:
For example:
What is the perimeter of this rectangle?
Perimeter = Length + Length + Breadth + Breadth
5cm
3cm 3cm
5cm

5. Summary
You can only find perimeter when the lengths
and breadths have the same units.
For example,
the length is 5 cm and the breadth is 4 cm.
The perimeter will be 18 cm.

6. Summary
You can only find perimeter when the length
and breadth have the same units.
For example,
the length is 5 m and the breadth is 4 m.
The area will be 18m.

7. A and B have the same area.
Find the unknown length, x.
B
A x cm
64cm²

8. A and B have the same area.
Find the unknown length, x.
B
A x cm
64cm²
___ x ___ = 64cm²

9. A and B have the same area.
Find the unknown length, x.
B
A x cm
64cm²
8 x 8 = 64
Therefore, x = 8cm

10. 2 similar rectangles overlapped each other.
Find the perimeter of the figure.
8 cm
4 cm 6 cm
4 cm

11. 2 similar rectangles overlapped each other.
Find the perimeter of the figure.
8 cm
4 cm 6 cm
4 cm
The length and breadth have the same value.

12. 2 similar rectangles overlapped each other.
Find the perimeter of the figure.
8 cm
4 cm 6 cm
6 cm 4 cm
8 cm
6 + 8 + 4 + 6 + 8 + 4 = ______ cm

13. 2 similar rectangles overlapped each other.
Find the perimeter of the figure.
8 cm
4 cm 6 cm
6 cm 4 cm
8 cm
6 + 8 + 4 + 6 + 8 + 4 = 36 cm

14. Are you ready to
try out the
questions?

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