Finding the Fourth Proportional to 8,978.32, 12,390.60 and 4,999.42

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.32 : 12,390.60 = 4,999.42 : x
2. Step 2: Convert to fraction form
   8,978.32/12,390.60 = 4,999.42/x
3. Step 3: Cross multiply
   8,978.32x = 12,390.60 × 4,999.42
4. Step 4: Simplify right side
   8,978.32x = 61,945,813.45
5. Step 5: Solve for x
   x = 61,945,813.45/8,978.32
6. Step 6: Final answer
   x = 6,899.49