Finding the Fourth Proportional to 612,978.76, 919,171.98 and 213,610.12

Step by Step Solution

1. Step 1: Write the proportion equation
   612,978.76 : 919,171.98 = 213,610.12 : x
2. Step 2: Convert to fraction form
   612,978.76/919,171.98 = 213,610.12/x
3. Step 3: Cross multiply
   612,978.76x = 919,171.98 × 213,610.12
4. Step 4: Simplify right side
   612,978.76x = 196,344,436,948.44
5. Step 5: Solve for x
   x = 196,344,436,948.44/612,978.76
6. Step 6: Final answer
   x = 320,311.97