Finding the Fourth Proportional to 1,005.57, 1,387.31 and 769.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.57 : 1,387.31 = 769.27 : x
2. Step 2: Convert to fraction form
   1,005.57/1,387.31 = 769.27/x
3. Step 3: Cross multiply
   1,005.57x = 1,387.31 × 769.27
4. Step 4: Simplify right side
   1,005.57x = 1,067,219.48
5. Step 5: Solve for x
   x = 1,067,219.48/1,005.57
6. Step 6: Final answer
   x = 1,061.31