Finding the Fourth Proportional to 1,389.96, 1,917.54 and 865.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.96 : 1,917.54 = 865.89 : x
2. Step 2: Convert to fraction form
   1,389.96/1,917.54 = 865.89/x
3. Step 3: Cross multiply
   1,389.96x = 1,917.54 × 865.89
4. Step 4: Simplify right side
   1,389.96x = 1,660,378.71
5. Step 5: Solve for x
   x = 1,660,378.71/1,389.96
6. Step 6: Final answer
   x = 1,194.55