A) \[90{}^\circ \]
B) \[72{}^\circ \]
C) \[60{}^\circ \]
D) \[54{}^\circ \]
Correct Answer: B
Solution :
Since side of pentagon, \[x=5\] \[\therefore \] Each interior \[=\frac{2\times 5-4}{5}\times {{90}^{o}}={{108}^{o}}\] Since \[\Delta \,\,CDE\] is an isosceles triangle \[\therefore \] \[2\angle CDB=180-108=72\] or \[\angle CDE={{36}^{o}}\] \[\therefore \] \[\angle BDE=108-{{36}^{o}}={{72}^{o}}\]You need to login to perform this action.
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