Shape
    
Some signalling flags

What different shapes do flags commonly have? Think of several reasons why these shapes are chosen. Most flags are rectangular in shape. Why is this shape most popular? Are rectangular flags always the same shape?                


        
             Canada                           Switzerland                        Bahrain        

Measure accurately and note down the dimensions of each of the illustrated flags. Are the side lengths all in the same ratio? Are any ratios the common ‘A4’ ratio? Investigate this. 

    


Flags are generally rectangular. Whatever shape they are, they need a straight (vertical) edge to thread the rope and align to the flagpole. A rectangle is most like a traditional ‘picture’ for display purposes. Furthermore, rectangles tessellate easily, leading to economies in production. Clearly from the given examples, different rectangular flags may have different shapes.


The actual flag sizes (in pixels) are

Bahrain: 108 180 ; Switzerland: 108 108 ;
Canada: 108 216 .

Hence the edges of the rectangles are not
in the same ratio.

The Bahrain flag ratio is the most common.

None of these ratios is the common A4 ratio,
in which the length is 2 times the width.

For a width of 108 (pixels) the length here would
be expected to be close on 153 pixels.