Finding the Fourth Proportional to 123,912.51, 171,002.98 and 87,678.91

Step by Step Solution

1. Step 1: Write the proportion equation
   123,912.51 : 171,002.98 = 87,678.91 : x
2. Step 2: Convert to fraction form
   123,912.51/171,002.98 = 87,678.91/x
3. Step 3: Cross multiply
   123,912.51x = 171,002.98 × 87,678.91
4. Step 4: Simplify right side
   123,912.51x = 14,993,354,893.15
5. Step 5: Solve for x
   x = 14,993,354,893.15/123,912.51
6. Step 6: Final answer
   x = 120,999.53