Finding the Fourth Proportional to 1,005.48, 1,387.50 and 557.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.48 : 1,387.50 = 557.32 : x
2. Step 2: Convert to fraction form
   1,005.48/1,387.50 = 557.32/x
3. Step 3: Cross multiply
   1,005.48x = 1,387.50 × 557.32
4. Step 4: Simplify right side
   1,005.48x = 773,281.50
5. Step 5: Solve for x
   x = 773,281.50/1,005.48
6. Step 6: Final answer
   x = 769.07