Finding the Fourth Proportional to 105,411.72, 157,942.62 and 85,699.56

Step by Step Solution

1. Step 1: Write the proportion equation
   105,411.72 : 157,942.62 = 85,699.56 : x
2. Step 2: Convert to fraction form
   105,411.72/157,942.62 = 85,699.56/x
3. Step 3: Cross multiply
   105,411.72x = 157,942.62 × 85,699.56
4. Step 4: Simplify right side
   105,411.72x = 13,535,613,039.25
5. Step 5: Solve for x
   x = 13,535,613,039.25/105,411.72
6. Step 6: Final answer
   x = 128,407.10