Finding the Fourth Proportional to 105,132.72, 145,086.16 and 57,389.12

Step by Step Solution

1. Step 1: Write the proportion equation
   105,132.72 : 145,086.16 = 57,389.12 : x
2. Step 2: Convert to fraction form
   105,132.72/145,086.16 = 57,389.12/x
3. Step 3: Cross multiply
   105,132.72x = 145,086.16 × 57,389.12
4. Step 4: Simplify right side
   105,132.72x = 8,326,367,046.58
5. Step 5: Solve for x
   x = 8,326,367,046.58/105,132.72
6. Step 6: Final answer
   x = 79,198.63