Finding the Fourth Proportional to 105,718.77, 145,898.42 and 57,978.99

Step by Step Solution

1. Step 1: Write the proportion equation
   105,718.77 : 145,898.42 = 57,978.99 : x
2. Step 2: Convert to fraction form
   105,718.77/145,898.42 = 57,978.99/x
3. Step 3: Cross multiply
   105,718.77x = 145,898.42 × 57,978.99
4. Step 4: Simplify right side
   105,718.77x = 8,459,042,744.30
5. Step 5: Solve for x
   x = 8,459,042,744.30/105,718.77
6. Step 6: Final answer
   x = 80,014.58