Finding the Fourth Proportional to 105,298.38, 145,409.31 and 67,638.78

Step by Step Solution

1. Step 1: Write the proportion equation
   105,298.38 : 145,409.31 = 67,638.78 : x
2. Step 2: Convert to fraction form
   105,298.38/145,409.31 = 67,638.78/x
3. Step 3: Cross multiply
   105,298.38x = 145,409.31 × 67,638.78
4. Step 4: Simplify right side
   105,298.38x = 9,835,308,329.04
5. Step 5: Solve for x
   x = 9,835,308,329.04/105,298.38
6. Step 6: Final answer
   x = 93,404.18