Finding the Fourth Proportional to 13,607.31, 18,778.10 and 7,638.42

Step by Step Solution

1. Step 1: Write the proportion equation
   13,607.31 : 18,778.10 = 7,638.42 : x
2. Step 2: Convert to fraction form
   13,607.31/18,778.10 = 7,638.42/x
3. Step 3: Cross multiply
   13,607.31x = 18,778.10 × 7,638.42
4. Step 4: Simplify right side
   13,607.31x = 143,435,014.60
5. Step 5: Solve for x
   x = 143,435,014.60/13,607.31
6. Step 6: Final answer
   x = 10,541.03