Finding the Fourth Proportional to 31,978.96, 47,961.10 and 8,607.20

Step by Step Solution

1. Step 1: Write the proportion equation
   31,978.96 : 47,961.10 = 8,607.20 : x
2. Step 2: Convert to fraction form
   31,978.96/47,961.10 = 8,607.20/x
3. Step 3: Cross multiply
   31,978.96x = 47,961.10 × 8,607.20
4. Step 4: Simplify right side
   31,978.96x = 412,810,779.92
5. Step 5: Solve for x
   x = 412,810,779.92/31,978.96
6. Step 6: Final answer
   x = 12,908.82