Finding the Fourth Proportional to 1,016.15, 1,401.75 and 642.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.15 : 1,401.75 = 642.48 : x
2. Step 2: Convert to fraction form
   1,016.15/1,401.75 = 642.48/x
3. Step 3: Cross multiply
   1,016.15x = 1,401.75 × 642.48
4. Step 4: Simplify right side
   1,016.15x = 900,591.08
5. Step 5: Solve for x
   x = 900,591.08/1,016.15
6. Step 6: Final answer
   x = 886.28