Finding the Fourth Proportional to 123,900.78, 170,985.15 and 67,312.20

Step by Step Solution

1. Step 1: Write the proportion equation
   123,900.78 : 170,985.15 = 67,312.20 : x
2. Step 2: Convert to fraction form
   123,900.78/170,985.15 = 67,312.20/x
3. Step 3: Cross multiply
   123,900.78x = 170,985.15 × 67,312.20
4. Step 4: Simplify right side
   123,900.78x = 11,509,386,613.83
5. Step 5: Solve for x
   x = 11,509,386,613.83/123,900.78
6. Step 6: Final answer
   x = 92,891.96