Finding the Fourth Proportional to 89,905.56, 134,885.10 and 39,978.78

Step by Step Solution

1. Step 1: Write the proportion equation
   89,905.56 : 134,885.10 = 39,978.78 : x
2. Step 2: Convert to fraction form
   89,905.56/134,885.10 = 39,978.78/x
3. Step 3: Cross multiply
   89,905.56x = 134,885.10 × 39,978.78
4. Step 4: Simplify right side
   89,905.56x = 5,392,541,738.18
5. Step 5: Solve for x
   x = 5,392,541,738.18/89,905.56
6. Step 6: Final answer
   x = 59,980.07