Finding the Fourth Proportional to 86,801.58, 129,990.04 and 78,387.10

Step by Step Solution

1. Step 1: Write the proportion equation
   86,801.58 : 129,990.04 = 78,387.10 : x
2. Step 2: Convert to fraction form
   86,801.58/129,990.04 = 78,387.10/x
3. Step 3: Cross multiply
   86,801.58x = 129,990.04 × 78,387.10
4. Step 4: Simplify right side
   86,801.58x = 10,189,542,264.48
5. Step 5: Solve for x
   x = 10,189,542,264.48/86,801.58
6. Step 6: Final answer
   x = 117,388.90