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UKMT Senior Mathematical Challenge, 2019

Geometry Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

Alison folds a square piece of paper in half along the dashed line shown in the diagram. After opening the paper out again, she then folds one of the corners onto the dashed line. What is the value of $\alpha$ ?

(A) $45$ (B) $60$ (C) $65$ (D) $70$ (E) $75$

Figure for this problem

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