Answer: 3/5
=========================================================
Explanation:
For any right triangle, the sine of an acute angle is equal to the opposite over hypotenuse.
So we can say
sin(angle) = opposite/hypotenuse
sin(A) = 3/5
Note how the side that's 3 units long is as far away from angle A as possible, which is why it's considered the opposite side. The hypotenuse 5 is the longest side of the triangle. The hypotenuse is always the longest side, and always opposite the 90 degree angle.
