Finding the Fourth Proportional to 1,016.20, 1,402.22 and 642.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.20 : 1,402.22 = 642.52 : x
2. Step 2: Convert to fraction form
   1,016.20/1,402.22 = 642.52/x
3. Step 3: Cross multiply
   1,016.20x = 1,402.22 × 642.52
4. Step 4: Simplify right side
   1,016.20x = 900,944.17
5. Step 5: Solve for x
   x = 900,944.17/1,016.20
6. Step 6: Final answer
   x = 886.59