Finding the Fourth Proportional to 13,686.74, 18,887.70 and 7,399.12

Step by Step Solution

1. Step 1: Write the proportion equation
   13,686.74 : 18,887.70 = 7,399.12 : x
2. Step 2: Convert to fraction form
   13,686.74/18,887.70 = 7,399.12/x
3. Step 3: Cross multiply
   13,686.74x = 18,887.70 × 7,399.12
4. Step 4: Simplify right side
   13,686.74x = 139,752,358.82
5. Step 5: Solve for x
   x = 139,752,358.82/13,686.74
6. Step 6: Final answer
   x = 10,210.78