ExplanationTo help with discussion, we have labeled points on the figure.
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Start with triangle ACF. Angle A is 90° and angle C is 30°, so angle AFC must be 60° (180° – 90° – 30° = 60°).
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If AFC is 60°, then EFD must be 120° (180° – 60° = 120°).
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Now you can find angle FDE, which we have called angle z: (180° – 120° – 40° = 20°). If z = 20°, then x = 160°, because x + z = 180°.
Hence x x = 160°.Attachment:
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