Finding the Fourth Proportional to 69,978.60, 104,880.42 and 55,128.87

Step by Step Solution

1. Step 1: Write the proportion equation
   69,978.60 : 104,880.42 = 55,128.87 : x
2. Step 2: Convert to fraction form
   69,978.60/104,880.42 = 55,128.87/x
3. Step 3: Cross multiply
   69,978.60x = 104,880.42 × 55,128.87
4. Step 4: Simplify right side
   69,978.60x = 5,781,939,039.73
5. Step 5: Solve for x
   x = 5,781,939,039.73/69,978.60
6. Step 6: Final answer
   x = 82,624.39