Finding the Fourth Proportional to 105,392.72, 145,438.88 and 57,645.05

Step by Step Solution

1. Step 1: Write the proportion equation
   105,392.72 : 145,438.88 = 57,645.05 : x
2. Step 2: Convert to fraction form
   105,392.72/145,438.88 = 57,645.05/x
3. Step 3: Cross multiply
   105,392.72x = 145,438.88 × 57,645.05
4. Step 4: Simplify right side
   105,392.72x = 8,383,830,494.12
5. Step 5: Solve for x
   x = 8,383,830,494.12/105,392.72
6. Step 6: Final answer
   x = 79,548.48