Finding the Fourth Proportional to 12.31, 18.38 and 10.71

Step by Step Solution

1. Step 1: Write the proportion equation
   12.31 : 18.38 = 10.71 : x
2. Step 2: Convert to fraction form
   12.31/18.38 = 10.71/x
3. Step 3: Cross multiply
   12.31x = 18.38 × 10.71
4. Step 4: Simplify right side
   12.31x = 196.85
5. Step 5: Solve for x
   x = 196.85/12.31
6. Step 6: Final answer
   x = 15.99