Answer:
C. 
Step-by-step explanation:
Recall: SOHCAHTOA
Thus,

Reference angle = 28°
Adjacent = 15
Hypotenuse = 17
Plug in the values

Step-by-step explanation:
Volume of displaced water = (10cm)(10cm)(1.6cm)
= 160 cm^3
density = mass/vol of displaced water
= 3088 grams/160 cm^3
= 19.3 g/cm^3
P.S. This is most likely a pure gold medallion.
Required expression is x/9 - 7