Finding the Fourth Proportional to 139.42, 192.18 and 111.70

Step by Step Solution

1. Step 1: Write the proportion equation
   139.42 : 192.18 = 111.70 : x
2. Step 2: Convert to fraction form
   139.42/192.18 = 111.70/x
3. Step 3: Cross multiply
   139.42x = 192.18 × 111.70
4. Step 4: Simplify right side
   139.42x = 21,466.51
5. Step 5: Solve for x
   x = 21,466.51/139.42
6. Step 6: Final answer
   x = 153.97