Finding the Fourth Proportional to 78,689.28, 108,589.86 and 42,879.60

Step by Step Solution

1. Step 1: Write the proportion equation
   78,689.28 : 108,589.86 = 42,879.60 : x
2. Step 2: Convert to fraction form
   78,689.28/108,589.86 = 42,879.60/x
3. Step 3: Cross multiply
   78,689.28x = 108,589.86 × 42,879.60
4. Step 4: Simplify right side
   78,689.28x = 4,656,289,760.86
5. Step 5: Solve for x
   x = 4,656,289,760.86/78,689.28
6. Step 6: Final answer
   x = 59,173.11