Finding the Fourth Proportional to 105,728.69, 145,905.78 and 57,982.37

Step by Step Solution

1. Step 1: Write the proportion equation
   105,728.69 : 145,905.78 = 57,982.37 : x
2. Step 2: Convert to fraction form
   105,728.69/145,905.78 = 57,982.37/x
3. Step 3: Cross multiply
   105,728.69x = 145,905.78 × 57,982.37
4. Step 4: Simplify right side
   105,728.69x = 8,459,962,921.10
5. Step 5: Solve for x
   x = 8,459,962,921.10/105,728.69
6. Step 6: Final answer
   x = 80,015.77