Perimeter of Composite 2-D Shapes

To find the perimeter of composite 2-D shapes, we have to add up the lengths of all the sides of the joined shapes.

Calculate the perimeter of  the following shapes.

Worked Example 1:

Solution

The composite shape is made up of  a rectangle and a triangle.     

Perimeter = the total length of its sides

                 = ( 6 + 6 + 2 + 4 + 8 + 4 ) cm

                 = 30 cm

            

 Worked Example 2: 

Solution

The composite shape is made up of  a square and a triangle.     


Perimeter = the total length of its sides
                 = ( 4 + 4 + 4 + 4 + 8 + 8 ) cm
                 =   32 cm

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                          So children, time to sing a song.

                          Do enjoy yourself and have fun.

                                    Perimeter Song

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