Finding the Fourth Proportional to 1,084.60, 1,496.74 and 642.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,084.60 : 1,496.74 = 642.72 : x
2. Step 2: Convert to fraction form
   1,084.60/1,496.74 = 642.72/x
3. Step 3: Cross multiply
   1,084.60x = 1,496.74 × 642.72
4. Step 4: Simplify right side
   1,084.60x = 961,984.73
5. Step 5: Solve for x
   x = 961,984.73/1,084.60
6. Step 6: Final answer
   x = 886.95