Finding the Fourth Proportional to 1,005.62, 1,387.68 and 612.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.62 : 1,387.68 = 612.59 : x
2. Step 2: Convert to fraction form
   1,005.62/1,387.68 = 612.59/x
3. Step 3: Cross multiply
   1,005.62x = 1,387.68 × 612.59
4. Step 4: Simplify right side
   1,005.62x = 850,078.89
5. Step 5: Solve for x
   x = 850,078.89/1,005.62
6. Step 6: Final answer
   x = 845.33