Finding the Fourth Proportional to 83.89, 125.78 and 42.73

Step by Step Solution

1. Step 1: Write the proportion equation
   83.89 : 125.78 = 42.73 : x
2. Step 2: Convert to fraction form
   83.89/125.78 = 42.73/x
3. Step 3: Cross multiply
   83.89x = 125.78 × 42.73
4. Step 4: Simplify right side
   83.89x = 5,374.17
5. Step 5: Solve for x
   x = 5,374.17/83.89
6. Step 6: Final answer
   x = 64.07