Finding the Fourth Proportional to 12,429.45, 18,638.10 and 7,686.09

Step by Step Solution

1. Step 1: Write the proportion equation
   12,429.45 : 18,638.10 = 7,686.09 : x
2. Step 2: Convert to fraction form
   12,429.45/18,638.10 = 7,686.09/x
3. Step 3: Cross multiply
   12,429.45x = 18,638.10 × 7,686.09
4. Step 4: Simplify right side
   12,429.45x = 143,254,114.03
5. Step 5: Solve for x
   x = 143,254,114.03/12,429.45
6. Step 6: Final answer
   x = 11,525.38