Finding the Fourth Proportional to 105,729, 145,892.61 and 57,969.78

Step by Step Solution

1. Step 1: Write the proportion equation
   105,729 : 145,892.61 = 57,969.78 : x
2. Step 2: Convert to fraction form
   105,729/145,892.61 = 57,969.78/x
3. Step 3: Cross multiply
   105,729x = 145,892.61 × 57,969.78
4. Step 4: Simplify right side
   105,729x = 8,457,362,505.33
5. Step 5: Solve for x
   x = 8,457,362,505.33/105,729
6. Step 6: Final answer
   x = 79,990.94