Question: The ratio of the numbers of sides of two regular polygons is 1: 2. If each interior angle of the first polygon is $ 120{}^\circ , $ then the measure of each interior angle of the second polygon is
Options:
A) $ 140{}^\circ $
B) $ 135{}^\circ $
C) $ 150{}^\circ $
D) $ 160{}^\circ $
Show Answer
Answer:
Correct Answer: C
Solution:
- Given, interior angle of the first polygon $ =120{}^\circ $
Let number of sides in first polygon be $ n _1 $
Then, $ \frac{n _1-2}{n _1}\times 180{}^\circ =120{}^\circ $
$ \Rightarrow $ $ 3n _1-6=2n _1 $
$ \Rightarrow $ $ n _1=6 $
$ \because $ Sides of the second polygon $ =6n=6\times 2=12 $
$ \therefore $ Interior angle of the second polygon
$ =\frac{12-2}{12}\times 180{}^\circ =150{}^\circ $