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3 years ago

If a polygon has 189 diagonals how many sides does the polygon have ?

Mathematics

2 answers:

Damm [24]3 years ago

7 0

N(n-3)/2=189
n(n-3)=378
n^2-3n-378=0
n=21

Natali [406]3 years ago

5 0

<span>(n take 2) minus n = 189
n(n-3)/2 = 189
n(n-3) = 378
n^2-3n-378 = 0
n=21

</span>

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$\qquad\qquad\huge\underline{{\sf Answer}}$

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