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Question
The three angles of a quadrilateral are 100°, 60°, 70°. Find the fourth angle.
Solution
The three angles of the quadrilateral are 100°, 60°, 70°.
Let the fourth angle be x°,
Since, the sum of the angles of a quadrilateral is 360°.
∴ 100° + 60° + 70° + x° = 360°
230° + x° = 360°
x = 360° – 230° = 130°
Hence, the fourth angle is 130°.
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