Finding the Fourth Proportional to 139.76, 192.71 and 120.15

Step by Step Solution

1. Step 1: Write the proportion equation
   139.76 : 192.71 = 120.15 : x
2. Step 2: Convert to fraction form
   139.76/192.71 = 120.15/x
3. Step 3: Cross multiply
   139.76x = 192.71 × 120.15
4. Step 4: Simplify right side
   139.76x = 23,153.51
5. Step 5: Solve for x
   x = 23,153.51/139.76
6. Step 6: Final answer
   x = 165.67