Question

13. The measure of each interior angle of a regular polygon is 140o, then number of sides
that regular polygon has ________________
(a) 15 (b) 12 (c) 9 (d) 10

Answer 1

140*9 = 1260
1260/90 = 14
polygon has 5 side 
so = 14 - 5 = 9
so ans. is (c) 9