Answer: C) 12/13
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Step-by-step explanation:
Use the pythagorean theorem
a^2+b^2 = c^2
to find that c = 13 when a = 12 and b = 5.
So that makes the hypotenuse MO = 13 units long.
The opposite side is MN = 12 units long as this side is furthest we can get from angle O.
The sine ratio involves opposite over hypotenuse
sin(angle) = opposite/hypotenuse
sin(O) = MN/MO
sin(O) = 12/13