Answer:
115°
Step-by-step explanation:
The sum of angle measures of a pentagon is 540°, so your unknown angle can be found from ...
... 103° + 100° +110° +112° +unknown = 540°
... unknown = 540° -425° = 115° . . . . . . . . subtract 425° from both sides
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Angles of a polygon
The external angles lf a convex polygon always sum to 360°. The sum of internal and external angles is, of course, 180°. So, an n-sided polygon has internal angle measures that sum to ...
... n×180° - 360° = 180°×(n -2)
Thus, a pentagon has internal angles that sum to ...
... 180°×(5 - 2) = 540°
