Finding the Fourth Proportional to 105,300.12, 145,309.80 and 57,555.12

Step by Step Solution

1. Step 1: Write the proportion equation
   105,300.12 : 145,309.80 = 57,555.12 : x
2. Step 2: Convert to fraction form
   105,300.12/145,309.80 = 57,555.12/x
3. Step 3: Cross multiply
   105,300.12x = 145,309.80 × 57,555.12
4. Step 4: Simplify right side
   105,300.12x = 8,363,322,976.18
5. Step 5: Solve for x
   x = 8,363,322,976.18/105,300.12
6. Step 6: Final answer
   x = 79,423.68