Finding the Fourth Proportional to 1,016.52, 1,403.46 and 643.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.52 : 1,403.46 = 643.72 : x
2. Step 2: Convert to fraction form
   1,016.52/1,403.46 = 643.72/x
3. Step 3: Cross multiply
   1,016.52x = 1,403.46 × 643.72
4. Step 4: Simplify right side
   1,016.52x = 903,435.27
5. Step 5: Solve for x
   x = 903,435.27/1,016.52
6. Step 6: Final answer
   x = 888.75