Finding the Fourth Proportional to 12,421.42, 17,115.60 and 8,435.61

Step by Step Solution

1. Step 1: Write the proportion equation
   12,421.42 : 17,115.60 = 8,435.61 : x
2. Step 2: Convert to fraction form
   12,421.42/17,115.60 = 8,435.61/x
3. Step 3: Cross multiply
   12,421.42x = 17,115.60 × 8,435.61
4. Step 4: Simplify right side
   12,421.42x = 144,380,558.15
5. Step 5: Solve for x
   x = 144,380,558.15/12,421.42
6. Step 6: Final answer
   x = 11,623.52