Finding the Fourth Proportional to 85,784.78, 128,534.90 and 60,700.50

Step by Step Solution

1. Step 1: Write the proportion equation
   85,784.78 : 128,534.90 = 60,700.50 : x
2. Step 2: Convert to fraction form
   85,784.78/128,534.90 = 60,700.50/x
3. Step 3: Cross multiply
   85,784.78x = 128,534.90 × 60,700.50
4. Step 4: Simplify right side
   85,784.78x = 7,802,132,697.45
5. Step 5: Solve for x
   x = 7,802,132,697.45/85,784.78
6. Step 6: Final answer
   x = 90,950.08