Finding the Fourth Proportional to 1,084.31, 1,496.55 and 642.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,084.31 : 1,496.55 = 642.23 : x
2. Step 2: Convert to fraction form
   1,084.31/1,496.55 = 642.23/x
3. Step 3: Cross multiply
   1,084.31x = 1,496.55 × 642.23
4. Step 4: Simplify right side
   1,084.31x = 961,129.31
5. Step 5: Solve for x
   x = 961,129.31/1,084.31
6. Step 6: Final answer
   x = 886.40