Finding the Fourth Proportional to 81,151.78, 121,754.72 and 51,131.37

Step by Step Solution

1. Step 1: Write the proportion equation
   81,151.78 : 121,754.72 = 51,131.37 : x
2. Step 2: Convert to fraction form
   81,151.78/121,754.72 = 51,131.37/x
3. Step 3: Cross multiply
   81,151.78x = 121,754.72 × 51,131.37
4. Step 4: Simplify right side
   81,151.78x = 6,225,485,393.30
5. Step 5: Solve for x
   x = 6,225,485,393.30/81,151.78
6. Step 6: Final answer
   x = 76,714.09