Question

How many sides does a polygon have if the sum of its interior angles is 1,260º?

A. 7
B. 8
C. 9
D. 10

Answer 1

the sum of interior angle is = 180(n-2) where n denotes the number of sides
so 1260° =180(n-2),  n -2= 1,280/180=7, so n=7+2=9
the answer is C. 9