Finding the Fourth Proportional to 1,013.78, 1,401.06 and 765.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,013.78 : 1,401.06 = 765.02 : x
2. Step 2: Convert to fraction form
   1,013.78/1,401.06 = 765.02/x
3. Step 3: Cross multiply
   1,013.78x = 1,401.06 × 765.02
4. Step 4: Simplify right side
   1,013.78x = 1,071,838.92
5. Step 5: Solve for x
   x = 1,071,838.92/1,013.78
6. Step 6: Final answer
   x = 1,057.27