x + 35° + 90° = 180°
x = 180° - 35° - 90°
x = 55°
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x + 35° + 15° = 180°
x = 180° - 35° - 15°
x = 130°
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x + 20° + 20° = 180°
x = 180° - 20° - 20
x = 140°
