A) 5
B) 6
C) 7
D) 8
Correct Answer: B
Solution :
Here, (interior angle) \[-\] (exterior angle) \[=60{}^\circ \] \[\Rightarrow \] \[\frac{(n-2)\times 180}{n}-\frac{360}{n}=60\] \[\Rightarrow \] \[\frac{1}{n}[(n-2)\times 180-360]=60\] \[\Rightarrow \] \[\frac{1}{n}[180\,n-360-360]=60\] \[\Rightarrow \] \[\frac{1}{n}[180\,n-720]=60\] \[\Rightarrow \] \[180\,n-720=60n\] \[\Rightarrow \] \[180\,n-60\,n=720\] \[\Rightarrow \] \[120\,n=720\] \[\therefore \] \[n=6\] Therefore, the polygon contains 6 sides.You need to login to perform this action.
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