Finding the Fourth Proportional to 9,429.60, 12,985.20 and 8,641.12

Step by Step Solution

1. Step 1: Write the proportion equation
   9,429.60 : 12,985.20 = 8,641.12 : x
2. Step 2: Convert to fraction form
   9,429.60/12,985.20 = 8,641.12/x
3. Step 3: Cross multiply
   9,429.60x = 12,985.20 × 8,641.12
4. Step 4: Simplify right side
   9,429.60x = 112,206,671.42
5. Step 5: Solve for x
   x = 112,206,671.42/9,429.60
6. Step 6: Final answer
   x = 11,899.41