Finding the Fourth Proportional to 85,782.78, 128,531.90 and 60,698.50

Step by Step Solution

1. Step 1: Write the proportion equation
   85,782.78 : 128,531.90 = 60,698.50 : x
2. Step 2: Convert to fraction form
   85,782.78/128,531.90 = 60,698.50/x
3. Step 3: Cross multiply
   85,782.78x = 128,531.90 × 60,698.50
4. Step 4: Simplify right side
   85,782.78x = 7,801,693,532.15
5. Step 5: Solve for x
   x = 7,801,693,532.15/85,782.78
6. Step 6: Final answer
   x = 90,947.08