Finding the Fourth Proportional to 8,978.99, 12,390.51 and 4,999.38

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.99 : 12,390.51 = 4,999.38 : x
2. Step 2: Convert to fraction form
   8,978.99/12,390.51 = 4,999.38/x
3. Step 3: Cross multiply
   8,978.99x = 12,390.51 × 4,999.38
4. Step 4: Simplify right side
   8,978.99x = 61,944,867.88
5. Step 5: Solve for x
   x = 61,944,867.88/8,978.99
6. Step 6: Final answer
   x = 6,898.87