You are asked for an angle. You need to use the inverse sine.
The answer is about 30 degrees. See below.
Step-by-step explanation:
Sin(y) = opposite / hypotenuse
opposite = 9cm
hypotenuse = 17 cm
Sin(y) = 9/17
y = sin-1(9/17)
y = sin-1(31.97) degrees.
To the nearest 1/10 of a degree, it would be
y = 32.0 degrees.