Finding the Fourth Proportional to 105,408.72, 157,938.12 and 85,696.56

Step by Step Solution

1. Step 1: Write the proportion equation
   105,408.72 : 157,938.12 = 85,696.56 : x
2. Step 2: Convert to fraction form
   105,408.72/157,938.12 = 85,696.56/x
3. Step 3: Cross multiply
   105,408.72x = 157,938.12 × 85,696.56
4. Step 4: Simplify right side
   105,408.72x = 13,534,753,576.87
5. Step 5: Solve for x
   x = 13,534,753,576.87/105,408.72
6. Step 6: Final answer
   x = 128,402.60