Finding the Fourth Proportional to 1,387.71, 1,914.71 and 863.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.71 : 1,914.71 = 863.37 : x
2. Step 2: Convert to fraction form
   1,387.71/1,914.71 = 863.37/x
3. Step 3: Cross multiply
   1,387.71x = 1,914.71 × 863.37
4. Step 4: Simplify right side
   1,387.71x = 1,653,098.86
5. Step 5: Solve for x
   x = 1,653,098.86/1,387.71
6. Step 6: Final answer
   x = 1,191.24