an angle of a regular polygon is given by a formula \(\frac{(n-2)*180}{n}\)

Hence we have y = \(\frac{(n-2)*180}{n}\)

here, \(n\) = no of sides of the polygon

\(X\) here is an external angle of the polygon

external angles of a regular polygon add up to 360 degrees

therefore \(x = 360/n\)

Given that,

\(y = 5X\)

\(5X =\) \(\frac{(n-2)*180}{n}\)

\(5X*n = (n-2)*180\)

\(5* 360 = (n-2)*180\)

solve for n; \(n = 12\)

option D

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This is my response to the question and may be incorrect. Feel free to rectify any mistakes