Finding the Fourth Proportional to 1,388.88, 1,917.54 and 865.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.88 : 1,917.54 = 865.68 : x
2. Step 2: Convert to fraction form
   1,388.88/1,917.54 = 865.68/x
3. Step 3: Cross multiply
   1,388.88x = 1,917.54 × 865.68
4. Step 4: Simplify right side
   1,388.88x = 1,659,976.03
5. Step 5: Solve for x
   x = 1,659,976.03/1,388.88
6. Step 6: Final answer
   x = 1,195.19