Answer:
15/17
Step-by-step explanation:
in the described scenario AB is the vertical leg of the right-angled triangle, that can be seen as the trigonometric triangle of the angle at C.
this triangle would be inscribed inside a circle with the center at C and the radius being BC.
the sine value of an angle is the length of the vertical leg of the trigonometric triangle inside the normed circle with radius 1.
if inside a larger circle, to get the sine value, these lengths must be scaled back to the norm of radius = 1.
and that is what the sine ratio is : the actual length of the vertical leg scaled to the radius of 1 (by dividing it by the actual radius) :
sin(theta) = AB / BC = 15/17
FYI
sin(theta) = 15/17 = 0.882352941...
and the angle theta is then 61.92751306...°
cos(theta) = CA / BC = 8/17 = 0.470588235...
and of course, this gives us the same angle.
