Finding the Fourth Proportional to 87,111.30, 130,764.15 and 81,400.80

Step by Step Solution

1. Step 1: Write the proportion equation
   87,111.30 : 130,764.15 = 81,400.80 : x
2. Step 2: Convert to fraction form
   87,111.30/130,764.15 = 81,400.80/x
3. Step 3: Cross multiply
   87,111.30x = 130,764.15 × 81,400.80
4. Step 4: Simplify right side
   87,111.30x = 10,644,306,421.32
5. Step 5: Solve for x
   x = 10,644,306,421.32/87,111.30
6. Step 6: Final answer
   x = 122,192.03