Mte 181
posted by Nicki .
You have a heptagon with the following interior angles 125, 130, 175, 105, 165, 25. What's the measurement of the 7th angle and why?

900  (125 + 130 + 175 + 105 + 165 + 25) = ?
http://www.coolmath.com/reference/polygons07heptagons.html 
The sum of the interior angles of a polygon with N sides is
180*(N2) degrees.
A heptagon has N=7 sides, so the sum is 900 degrees.
The seventh angle must be
900(125 +130 + 175 + 105 + 165 + 25)
= 175 degrees