Finding the Fourth Proportional to 1,389.37, 1,917.54 and 865.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.37 : 1,917.54 = 865.57 : x
2. Step 2: Convert to fraction form
   1,389.37/1,917.54 = 865.57/x
3. Step 3: Cross multiply
   1,389.37x = 1,917.54 × 865.57
4. Step 4: Simplify right side
   1,389.37x = 1,659,765.10
5. Step 5: Solve for x
   x = 1,659,765.10/1,389.37
6. Step 6: Final answer
   x = 1,194.62