2017 AMC 10B Problem 22
Problem 22 of 25HarderGeometry
The diameter of a circle of radius is extended to a point outside the circle so that Point is chosen so that and line is perpendicular to line Segment intersects the circle at a point between and What is the area of
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Solution
Since the radius is and we have Since and the angle at is a right angle, the area of is
By the Pythagorean Theorem, Also, is a right angle because is a diameter. The triangles share the angle at so by angle-angle similarity.
Their corresponding hypotenuses are and so their area ratio is Therefore,
Thus, the correct answer is D .