Finding the Fourth Proportional to 139.02, 208.37 and 57.89

Step by Step Solution

1. Step 1: Write the proportion equation
   139.02 : 208.37 = 57.89 : x
2. Step 2: Convert to fraction form
   139.02/208.37 = 57.89/x
3. Step 3: Cross multiply
   139.02x = 208.37 × 57.89
4. Step 4: Simplify right side
   139.02x = 12,061.64
5. Step 5: Solve for x
   x = 12,061.64/139.02
6. Step 6: Final answer
   x = 86.76