Finding the Fourth Proportional to 103,689.35, 155,698.05 and 78,757.55

Step by Step Solution

1. Step 1: Write the proportion equation
   103,689.35 : 155,698.05 = 78,757.55 : x
2. Step 2: Convert to fraction form
   103,689.35/155,698.05 = 78,757.55/x
3. Step 3: Cross multiply
   103,689.35x = 155,698.05 × 78,757.55
4. Step 4: Simplify right side
   103,689.35x = 12,262,396,957.78
5. Step 5: Solve for x
   x = 12,262,396,957.78/103,689.35
6. Step 6: Final answer
   x = 118,260.91