Finding the Fourth Proportional to 8,978.10, 12,389.16 and 4,999.10

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.10 : 12,389.16 = 4,999.10 : x
2. Step 2: Convert to fraction form
   8,978.10/12,389.16 = 4,999.10/x
3. Step 3: Cross multiply
   8,978.10x = 12,389.16 × 4,999.10
4. Step 4: Simplify right side
   8,978.10x = 61,934,649.76
5. Step 5: Solve for x
   x = 61,934,649.76/8,978.10
6. Step 6: Final answer
   x = 6,898.41