Finding the Fourth Proportional to 31,780.08, 47,673.90 and 8,406.72

Step by Step Solution

1. Step 1: Write the proportion equation
   31,780.08 : 47,673.90 = 8,406.72 : x
2. Step 2: Convert to fraction form
   31,780.08/47,673.90 = 8,406.72/x
3. Step 3: Cross multiply
   31,780.08x = 47,673.90 × 8,406.72
4. Step 4: Simplify right side
   31,780.08x = 400,781,128.61
5. Step 5: Solve for x
   x = 400,781,128.61/31,780.08
6. Step 6: Final answer
   x = 12,611.08