Finding the Fourth Proportional to 21,910.56, 30,234.96 and 12,478.80

Step by Step Solution

1. Step 1: Write the proportion equation
   21,910.56 : 30,234.96 = 12,478.80 : x
2. Step 2: Convert to fraction form
   21,910.56/30,234.96 = 12,478.80/x
3. Step 3: Cross multiply
   21,910.56x = 30,234.96 × 12,478.80
4. Step 4: Simplify right side
   21,910.56x = 377,296,018.85
5. Step 5: Solve for x
   x = 377,296,018.85/21,910.56
6. Step 6: Final answer
   x = 17,219.83