Finding the Fourth Proportional to 85,788.78, 128,540.90 and 60,704.50

Step by Step Solution

1. Step 1: Write the proportion equation
   85,788.78 : 128,540.90 = 60,704.50 : x
2. Step 2: Convert to fraction form
   85,788.78/128,540.90 = 60,704.50/x
3. Step 3: Cross multiply
   85,788.78x = 128,540.90 × 60,704.50
4. Step 4: Simplify right side
   85,788.78x = 7,803,011,064.05
5. Step 5: Solve for x
   x = 7,803,011,064.05/85,788.78
6. Step 6: Final answer
   x = 90,956.08