• calculation of the perimeter of

∗ rectilinear figure

∗ rectangle

∗ square

What will we learn today?

Measurement Perimeter

What is Perimeter?

The perimeter is the total distance around the

outside of a 2D shape.

Perimeter of Simple Shapes

There are special formulas for certain shapes:

For example:

What is the perimeter of this rectangle?

5cm

3cm

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.

5cm

3cm

Length

Breadth

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

Try this out!

What is the perimeter of the square?

Try this out!

What is the perimeter of this square?

Let’s recall the formula:

Perimeter = Length + Length + Breadth + Breadth

Try this out!

What is the perimeter of this square?

A square has 4 equal sides.

Therefore,

Perimeter = Length + Length + Length + Length

= 4 x Length

Try this out!

What is the perimeter of the rectangle?

4 cm

10 cm

Try this out!

What is the perimeter of the rectangle?

Let’s recall the formula:

Perimeter = Length + Length + Breadth + Breadth

4 cm

10 cm

Try this out!

What is the perimeter of the rectangle?

Let’s recall the formula:

Perimeter = Length + Length + Breadth + Breadth

4 cm

10 cm

4 cm

10 cm

Try this out!

What is the perimeter of the rectangle?

Let’s recall the formula:

Perimeter = 10 + 10 + 4 + 4

= 28 cm

4 cm

10 cm

4 cm

10 cm

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.

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.

Are you ready to try out the questions?

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