Finding the Fourth Proportional to 13,689.94, 18,892.12 and 7,402.31

Step by Step Solution

1. Step 1: Write the proportion equation
   13,689.94 : 18,892.12 = 7,402.31 : x
2. Step 2: Convert to fraction form
   13,689.94/18,892.12 = 7,402.31/x
3. Step 3: Cross multiply
   13,689.94x = 18,892.12 × 7,402.31
4. Step 4: Simplify right side
   13,689.94x = 139,845,328.80
5. Step 5: Solve for x
   x = 139,845,328.80/13,689.94
6. Step 6: Final answer
   x = 10,215.19