Find Area Red of shaded region ? #3 | Math Olympiad Training

Book recommendations
Here are some of my book recommendations for preparing for math competitions, in roughly increasing levels of difficulty.
✔️Math Olympiad
✔️The Art of Problem Solving, Vol. 1: The Basics Paperback
✔️The Art of Problem Solving, Vol. 2: And Beyond Paperback
✔️Problem-Solving Strategies (Problem Books in Mathematics)
✔️Mathematical Olympiad Treasures 2nd ed.
✔️Mathematical Olympiad Challenges 2nd ed.
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algebra
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value X
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How do you solve
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Engineering
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measure of the red angle
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Find Area
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puzzles variety
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choose answer
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