Finding the Fourth Proportional to 1,084.71, 1,496.70 and 642.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,084.71 : 1,496.70 = 642.75 : x
2. Step 2: Convert to fraction form
   1,084.71/1,496.70 = 642.75/x
3. Step 3: Cross multiply
   1,084.71x = 1,496.70 × 642.75
4. Step 4: Simplify right side
   1,084.71x = 962,003.93
5. Step 5: Solve for x
   x = 962,003.93/1,084.71
6. Step 6: Final answer
   x = 886.88