Question #N638
The lengths of the sides of a right triangle are 5, 12, and 13. What is the cosine of the angle opposite the side of length 12?
A. 5/13
B. 12/13
C. 5/12
D. 12/5
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Correct Answer is: A
In a right triangle, the cosine of an angle is the ratio of the length of the adjacent side to the length of the hypotenuse. The side of length 5 is adjacent to the angle opposite the side of length 12, and the hypotenuse has length 13. Therefore, the cosine of the angle opposite the side of length 12 is 5/13.