Finding the Fourth Proportional to 13,688.87, 18,890.65 and 7,401.25

Step by Step Solution

1. Step 1: Write the proportion equation
   13,688.87 : 18,890.65 = 7,401.25 : x
2. Step 2: Convert to fraction form
   13,688.87/18,890.65 = 7,401.25/x
3. Step 3: Cross multiply
   13,688.87x = 18,890.65 × 7,401.25
4. Step 4: Simplify right side
   13,688.87x = 139,814,328.86
5. Step 5: Solve for x
   x = 139,814,328.86/13,688.87
6. Step 6: Final answer
   x = 10,213.72