Finding the Fourth Proportional to 1,084.31, 1,625.72 and 390.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,084.31 : 1,625.72 = 390.61 : x
2. Step 2: Convert to fraction form
   1,084.31/1,625.72 = 390.61/x
3. Step 3: Cross multiply
   1,084.31x = 1,625.72 × 390.61
4. Step 4: Simplify right side
   1,084.31x = 635,016.47
5. Step 5: Solve for x
   x = 635,016.47/1,084.31
6. Step 6: Final answer
   x = 585.64