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Two sides of a triangle are 5 and 8, and the angle between them is 60°. Find the third side.
A√89
B√39
C9
D7
Answer & Solution
Correct answer: D. 7
c² = 25 + 64 − 2(5)(8)cos 60° = 89 − 40 = 49, so c = 7.
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