Angles? solve figures problems

Let's solve plane figures problems! Once you have completed the basic questions from Stage 1 to Stage 4, try to solve the challenging problems on the Final Stage ! If you can't solve a ploblem, you can check the hint of the question or ask the answer to your friends via Twitter.
'Angles?' contains following contents: --- -The sum of the Angles of a triangle -Exterior angle of a triangle -Isosceles triangle -Right-angled triangle
-Vertical angle -Corresponding angle -Alternate angle
-Parallelogram
-The sum of the Angles of a quadrilateral -The sum of the Angles of a polygon
-Inscribed angles
-Alternate segment theorem
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