Finding the Fourth Proportional to 10,404.10, 15,620.55 and 8,215.30

Step by Step Solution

1. Step 1: Write the proportion equation
   10,404.10 : 15,620.55 = 8,215.30 : x
2. Step 2: Convert to fraction form
   10,404.10/15,620.55 = 8,215.30/x
3. Step 3: Cross multiply
   10,404.10x = 15,620.55 × 8,215.30
4. Step 4: Simplify right side
   10,404.10x = 128,327,504.42
5. Step 5: Solve for x
   x = 128,327,504.42/10,404.10
6. Step 6: Final answer
   x = 12,334.32