Finding the Fourth Proportional to 9,404.65, 12,978.39 and 5,212.90

Step by Step Solution

1. Step 1: Write the proportion equation
   9,404.65 : 12,978.39 = 5,212.90 : x
2. Step 2: Convert to fraction form
   9,404.65/12,978.39 = 5,212.90/x
3. Step 3: Cross multiply
   9,404.65x = 12,978.39 × 5,212.90
4. Step 4: Simplify right side
   9,404.65x = 67,655,049.23
5. Step 5: Solve for x
   x = 67,655,049.23/9,404.65
6. Step 6: Final answer
   x = 7,193.79