Which of the following expressions will find the sum of interior angles of a polygon with 14 sides?

14 (180) - 2

180 (14-2)

180 (14) - 2

180 (14)

Central angle of polygon with 14 sides is:

a = 360/14

that means that interior angle is:

b = (180 - 360/14) / 2

because sum of angles in a triangle is 180.

each triangle has 2*b angles and there are 14 angles. so sum of all those angles is:

2*b*14 = (180-360/14) / 2*14*2 = 180*14-360 = 180*14 - 2*180 = 180 * (14-2)

Answer is second option.