Find the measure of the unknown interior angle in an irregular hexagon with angles 140°, 80°, 145°, 155°, and 100°.
100°
The sum of interior angles of a hexagon (6 sides) is \((6 - 2) \times 180° = 4 \times 180° = 720°\).
Sum of the five known angles: \(140 + 80 + 145 + 155 + 100 = 620°\).
Unknown angle = \(720° - 620° = 100°\).
Hence, the unknown interior angle measures 100°.
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