# Why is completing the square called completing the square?

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#1
Hi

I know how to use the 'complete the square' method to solve quadratics. Very familiar with the process.

But I'd like to know at what stage in workings are we 'completing' a square - just interested to know why the process is called that.

Thanks.
0
9 years ago
#2
is not a 'square'.

completes the square.

0
9 years ago
#3
3
9 years ago
#4
Good question - I wondered the same thing at school and my teacher couldn't explain it to me.

e.g.

is not a perfect square. is not a perfect square as well but it does make up three of the four quadrants of a square, and , where the square is .* To fill in the gap and "complete the square" we add a 9 to both sides to get

*If this part is confusing to you, try drawing a square with length x+3.
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#5
Thanks to three of you for helpful answers - appreciate the time taken.

ugk4life - no thanks at all for your silly post.
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