Finding the Fourth Proportional to 105,728.51, 145,865.31 and 67,489.49

Step by Step Solution

1. Step 1: Write the proportion equation
   105,728.51 : 145,865.31 = 67,489.49 : x
2. Step 2: Convert to fraction form
   105,728.51/145,865.31 = 67,489.49/x
3. Step 3: Cross multiply
   105,728.51x = 145,865.31 × 67,489.49
4. Step 4: Simplify right side
   105,728.51x = 9,844,375,380.59
5. Step 5: Solve for x
   x = 9,844,375,380.59/105,728.51
6. Step 6: Final answer
   x = 93,109.94