Finding the Fourth Proportional to 1,387.34, 1,914.96 and 856.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.34 : 1,914.96 = 856.39 : x
2. Step 2: Convert to fraction form
   1,387.34/1,914.96 = 856.39/x
3. Step 3: Cross multiply
   1,387.34x = 1,914.96 × 856.39
4. Step 4: Simplify right side
   1,387.34x = 1,639,952.59
5. Step 5: Solve for x
   x = 1,639,952.59/1,387.34
6. Step 6: Final answer
   x = 1,182.08