A 28 sided polygon is called an Icosikaioctagon This link should help: http://www.math.com/tables/geometry/polygons.htm
12.4567890
If it's a regular 28-agon then each interior angle is: (26*180)/28 = 167.'142857' degrees recurring decimals 0.'142857'
Square
A regular 12-sided polygon is called a dodecagon - from the Greek dodeka, meaning 12, and gonus, meaning angle.
An irregular pentagon.
12.4567890
angle
angle
The name of the angle which has three sided polygon called Triangle.
icosikaioctagon
Providing that it is a regular 28 sided polgon then each interior angle will measure: 1670 8' 34.29''
If it's a regular 28-agon then each interior angle is: (26*180)/28 = 167.'142857' degrees recurring decimals 0.'142857'
Square
A regular 12-sided polygon is called a dodecagon - from the Greek dodeka, meaning 12, and gonus, meaning angle.
An irregular pentagon.
Ext.Angle = 360n (no. of sides_ Int.Angle = 180 - Ext.Angle. Substituting. Int.Angle = 180 - 360/n Hence Int.Angle = 180 - 360/28 Int.Anglr = 180 - 12.857.... Int.Angle = 167.142.... degrees.
The interior angles add up to 4680 degrees