Finding the Fourth Proportional to 8,978.94, 12,390.72 and 4,999.96

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.94 : 12,390.72 = 4,999.96 : x
2. Step 2: Convert to fraction form
   8,978.94/12,390.72 = 4,999.96/x
3. Step 3: Cross multiply
   8,978.94x = 12,390.72 × 4,999.96
4. Step 4: Simplify right side
   8,978.94x = 61,953,104.37
5. Step 5: Solve for x
   x = 61,953,104.37/8,978.94
6. Step 6: Final answer
   x = 6,899.82