Finding the Fourth Proportional to 139.29, 191.88 and 108.15

Step by Step Solution

1. Step 1: Write the proportion equation
   139.29 : 191.88 = 108.15 : x
2. Step 2: Convert to fraction form
   139.29/191.88 = 108.15/x
3. Step 3: Cross multiply
   139.29x = 191.88 × 108.15
4. Step 4: Simplify right side
   139.29x = 20,751.82
5. Step 5: Solve for x
   x = 20,751.82/139.29
6. Step 6: Final answer
   x = 148.98