Each of the interior angles of a regular polygon is 140^\circ. Calculate the sum of all the interior angles of the polygon.
A
1080°
B
1260°
C
2160°
D
1800°
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
Since each interior angle = 140^\circ;
Each exterior angle = 180^\circ - 140^\circ = 40^\circ
Number of sides of the polygon = \(\frac{360^\circ}{40^\circ}\)
= 9
Sum of angles in the polygon = 140^\circ x 9
= 1260^\circ
Source: Myschool Past Questions Archive (Record #55367)