Question 1000354
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What is the vertex defect at a vertex where an equilateral triangle, a square and a regular pentagon meet? What is the answer in degrees and as a fraction. 
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An equilateral triangle contributes  60°.


A square contributes  90°.


A regular pentagon contributes  {{{180*(n-2)/5}}} = {{{180*(5-2)/5}}} = 108°.


The sum of these angles is  60° + 90° + 108° = 258°.


A vertex defect &nbsp;(see &nbsp;<A HREF=https://en.wikipedia.org/wiki/Angular_defect>this article</A>&nbsp; from Wikipedia) &nbsp;is the difference between &nbsp;360°&nbsp; and this sum, &nbsp;i.e. &nbsp;360° - 258° = 102°.