Perimeters basic

Construction NumeracyCalculating Perimeters: Basic Shapes

Stonemasonry Department 2012

Perimeter

‘Perimeter is the distance around a two dimensional

shape, or the measurement of the

distance around something; the length of

the boundary.’

Wikipedia 2012

Perimeter of a Square5m

5m

Perimeter = 5 + 5 + 5 + 5Perimeter = 20m

orPerimeter = 5 x 4Perimeter = 20m

To calculate the perimeter of a square we add the lengths of each of the four sides. Because the sides of a square have

identical lengths we can use the following formula:

Perimeter of a Square = Length of One Side x 4

5m

5m

Perimeter of a Square

6m

6m

Perimeter = Length of one side x 4

Perimeter =

7m

7mPerimeter = Length of one side x 4

Perimeter =

Perimeter of a Square

3m

3m

9.4m

9.4m


Perimeter =


Perimeter =

Perimeter of a Rectangle

6m

4m

Perimeter = 6 + 4 + 6 + 4

Perimeter = 20m

To calculate the perimeter of a rectangle we add the lengths of all four sides. Remember to use the correct unit of

measurement when displaying your answer (e.g. m, mm, cm, km)


8m

6m

9m

8m

P = Side 1 + Side 2 + Side 3 + Side 4

Perimeter =


Perimeter =


3m

2m

5.2m

3m


Perimeter =


Perimeter =

Perimeter of a Triangle

6m

6m

Perimeter = Side 1 + Side 2 + Side 3

Perimeter = 6 + 6 + 6

Perimeter = 18m

To calculate the perimeter of a triangle you add the lengths of each of the three sides. You cannot assume that each side will

have the same length so check your answer carefully.

6m


4m

4m4mPerimeter = Side 1 + Side 2 + Side 3

Perimeter =


Perimeter =

6m

8m8m


8m

9m9mPerimeter = Side 1 + Side 2 + Side 3

Perimeter =


Perimeter =

8m

7m7m

Perimeters of Complex Shapes

Perimeters are commonly used in the construction industry and often the shapes we measure the perimeter of are not perfect

squares, rectangles and triangles but a combination of a number of them. Can you calculate the perimeter of the shape

shown above?

References

The image on the title slide of this presentation was sourced from Eric Gjerde’s photostream at: http://images.cdn.fotopedia.com/flickr-153047995-hd.jpgThis image was made available under creative commons

The definition of perimeter was sourced from wikipedia at:http://en.wikipedia.org/wiki/Perimeter

Developed by The Stonemasonry DepartmentCity of Glasgow College

2012

Education

Perimeters basic