Finding the Fourth Proportional to 105,128.20, 145,077.54 and 57,380.52

Step by Step Solution

1. Step 1: Write the proportion equation
   105,128.20 : 145,077.54 = 57,380.52 : x
2. Step 2: Convert to fraction form
   105,128.20/145,077.54 = 57,380.52/x
3. Step 3: Cross multiply
   105,128.20x = 145,077.54 × 57,380.52
4. Step 4: Simplify right side
   105,128.20x = 8,324,624,685.52
5. Step 5: Solve for x
   x = 8,324,624,685.52/105,128.20
6. Step 6: Final answer
   x = 79,185.46