Finding the Fourth Proportional to 83.31, 125.04 and 42.78

Step by Step Solution

1. Step 1: Write the proportion equation
   83.31 : 125.04 = 42.78 : x
2. Step 2: Convert to fraction form
   83.31/125.04 = 42.78/x
3. Step 3: Cross multiply
   83.31x = 125.04 × 42.78
4. Step 4: Simplify right side
   83.31x = 5,349.21
5. Step 5: Solve for x
   x = 5,349.21/83.31
6. Step 6: Final answer
   x = 64.21