Sum of inside angles of a polygon= 180º(n-2) n=number of sides. This polygon has 6 sides, the sum of all its angles would be=180º(6-2)=720 let´s: xº=inside angle xº=720º-sum of the others inside angles. xº=720º-(75º+130º+120º+105º+145º)=720º-575º=145º
