Finding the Fourth Proportional to 105,727.85, 145,905.90 and 57,978.05

Step by Step Solution

1. Step 1: Write the proportion equation
   105,727.85 : 145,905.90 = 57,978.05 : x
2. Step 2: Convert to fraction form
   105,727.85/145,905.90 = 57,978.05/x
3. Step 3: Cross multiply
   105,727.85x = 145,905.90 × 57,978.05
4. Step 4: Simplify right side
   105,727.85x = 8,459,339,565.50
5. Step 5: Solve for x
   x = 8,459,339,565.50/105,727.85
6. Step 6: Final answer
   x = 80,010.51