If the ratio of external angle and internal angle is 2 : 7. Find the number of sides of regular polygon?
Correct Answer : a ) 9Explanation :
According to the question
Let the common multiple be x
⇒ External angle = 2x
Internal angle = 7x
We know that
Sum of internal angle and external angle of any regular figure is 180°
⇒ 2x + 7x = 180°
⇒ x = 20°
Exterior angle = 2 * 20°
Number of side of a regular polygon=\(360^0 \over exterior \ angle\)
⇒Number of Side=\(360^0 \over 40^0\)
Hence, (a) is the correct answer.
Such type of question is asked in various government exams like SSC CGL, SSC MTS, SSC CPO, SSC CHSL, RRB JE, RRB NTPC, RRB GROUP D, RRB OFFICER SCALE-I, IBPS PO, IBPS SO, RRB Office Assistant, IBPS Clerk, RBI Assistant, IBPS RRB OFFICER SCALE 2&3, UPSC CDS etc.