Finding the Fourth Proportional to 139.24, 191.89 and 102.31

Step by Step Solution

1. Step 1: Write the proportion equation
   139.24 : 191.89 = 102.31 : x
2. Step 2: Convert to fraction form
   139.24/191.89 = 102.31/x
3. Step 3: Cross multiply
   139.24x = 191.89 × 102.31
4. Step 4: Simplify right side
   139.24x = 19,632.27
5. Step 5: Solve for x
   x = 19,632.27/139.24
6. Step 6: Final answer
   x = 141.00