Finding the Fourth Proportional to 13,688.69, 18,890.40 and 7,401.06

Step by Step Solution

1. Step 1: Write the proportion equation
   13,688.69 : 18,890.40 = 7,401.06 : x
2. Step 2: Convert to fraction form
   13,688.69/18,890.40 = 7,401.06/x
3. Step 3: Cross multiply
   13,688.69x = 18,890.40 × 7,401.06
4. Step 4: Simplify right side
   13,688.69x = 139,808,983.82
5. Step 5: Solve for x
   x = 139,808,983.82/13,688.69
6. Step 6: Final answer
   x = 10,213.47