Finding the Fourth Proportional to 139.05, 191.82 and 86.58

Step by Step Solution

1. Step 1: Write the proportion equation
   139.05 : 191.82 = 86.58 : x
2. Step 2: Convert to fraction form
   139.05/191.82 = 86.58/x
3. Step 3: Cross multiply
   139.05x = 191.82 × 86.58
4. Step 4: Simplify right side
   139.05x = 16,607.78
5. Step 5: Solve for x
   x = 16,607.78/139.05
6. Step 6: Final answer
   x = 119.44