Question

Find the value of the unknown interior angle x in the following figures:

Answer 1

(i) \(x + 50° = 115°\) (Exterior angle theorem) 
\(x = 115° - 50° = 65°\)

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(ii) \(70° + x = 100°\) (Exterior angle theorem) 
\(x = 100° - 70° = 30°\)

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(iii) \(x + 90° = 125°\) (Exterior angle theorem) 
\(x = 125° - 90° = 35°\)

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(iv) \(x + 60° = 120°\) (Exterior angle theorem) 
\(x = 120° - 60° = 60°\)

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(v) \(x + 30° = 80°\) (Exterior angle theorem) 
\(x = 80° - 30° = 50°\)

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(vi) \(x + 35° = 75°\) (Exterior angle theorem) 
\(x = 75º - 35º = 40°\)