Finding the Fourth Proportional to 155.31, 214.33 and 86.31

Step by Step Solution

1. Step 1: Write the proportion equation
   155.31 : 214.33 = 86.31 : x
2. Step 2: Convert to fraction form
   155.31/214.33 = 86.31/x
3. Step 3: Cross multiply
   155.31x = 214.33 × 86.31
4. Step 4: Simplify right side
   155.31x = 18,498.82
5. Step 5: Solve for x
   x = 18,498.82/155.31
6. Step 6: Final answer
   x = 119.11