Finding the Fourth Proportional to 123,408.57, 185,171.52 and 85,516.15

Step by Step Solution

1. Step 1: Write the proportion equation
   123,408.57 : 185,171.52 = 85,516.15 : x
2. Step 2: Convert to fraction form
   123,408.57/185,171.52 = 85,516.15/x
3. Step 3: Cross multiply
   123,408.57x = 185,171.52 × 85,516.15
4. Step 4: Simplify right side
   123,408.57x = 15,835,155,279.64
5. Step 5: Solve for x
   x = 15,835,155,279.64/123,408.57
6. Step 6: Final answer
   x = 128,314.88