Answer: 3/5
Step-by-step explanation:
For angle A, the side furthest from here is BC = 15. This is the opposite side for this reference angle.
The hypotenuse is AC = 25, which is the longest side of any right triangle (always opposite the 90 degree angle).
The sine ratio involves dividing the opposite over hypotenuse.
So,
sin(angle) = opposite/hypotenuse
sin(A) = BC/AC
sin(A) = 15/25
sin(A) = (3*5)/(5*5)
sin(A) = 3/5