Finding the Fourth Proportional to 12,985.31, 19,478.88 and 4,665.39

Step by Step Solution

1. Step 1: Write the proportion equation
   12,985.31 : 19,478.88 = 4,665.39 : x
2. Step 2: Convert to fraction form
   12,985.31/19,478.88 = 4,665.39/x
3. Step 3: Cross multiply
   12,985.31x = 19,478.88 × 4,665.39
4. Step 4: Simplify right side
   12,985.31x = 90,876,571.96
5. Step 5: Solve for x
   x = 90,876,571.96/12,985.31
6. Step 6: Final answer
   x = 6,998.42