Finding the Fourth Proportional to 12,111.20, 16,714.72 and 8,140.64

Step by Step Solution

1. Step 1: Write the proportion equation
   12,111.20 : 16,714.72 = 8,140.64 : x
2. Step 2: Convert to fraction form
   12,111.20/16,714.72 = 8,140.64/x
3. Step 3: Cross multiply
   12,111.20x = 16,714.72 × 8,140.64
4. Step 4: Simplify right side
   12,111.20x = 136,068,518.22
5. Step 5: Solve for x
   x = 136,068,518.22/12,111.20
6. Step 6: Final answer
   x = 11,234.93