Finding the Fourth Proportional to 13,688.93, 18,890.73 and 7,401.31

Step by Step Solution

1. Step 1: Write the proportion equation
   13,688.93 : 18,890.73 = 7,401.31 : x
2. Step 2: Convert to fraction form
   13,688.93/18,890.73 = 7,401.31/x
3. Step 3: Cross multiply
   13,688.93x = 18,890.73 × 7,401.31
4. Step 4: Simplify right side
   13,688.93x = 139,816,148.86
5. Step 5: Solve for x
   x = 139,816,148.86/13,688.93
6. Step 6: Final answer
   x = 10,213.81