Finding the Fourth Proportional to 85,514.18, 128,336.94 and 81,123.93

Step by Step Solution

1. Step 1: Write the proportion equation
   85,514.18 : 128,336.94 = 81,123.93 : x
2. Step 2: Convert to fraction form
   85,514.18/128,336.94 = 81,123.93/x
3. Step 3: Cross multiply
   85,514.18x = 128,336.94 × 81,123.93
4. Step 4: Simplify right side
   85,514.18x = 10,411,196,936.97
5. Step 5: Solve for x
   x = 10,411,196,936.97/85,514.18
6. Step 6: Final answer
   x = 121,748.20