Finding the Fourth Proportional to 1,386.88, 1,913.89 and 765.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.88 : 1,913.89 = 765.92 : x
2. Step 2: Convert to fraction form
   1,386.88/1,913.89 = 765.92/x
3. Step 3: Cross multiply
   1,386.88x = 1,913.89 × 765.92
4. Step 4: Simplify right side
   1,386.88x = 1,465,875.14
5. Step 5: Solve for x
   x = 1,465,875.14/1,386.88
6. Step 6: Final answer
   x = 1,056.96