What is the average number of books read by 25 students in a year if 5 of them read 10 books, 10 of them read 7 books, and the other 10 students read 5 books?
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What is the measure of the third angle in a right triangle if the other two angles measure 45° and 90°?
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What is the maximum value of the cosine function within the interval \([-4\pi,4\pi]\)?