Finding the Fourth Proportional to 139.63, 209.31 and 112.42

Step by Step Solution

1. Step 1: Write the proportion equation
   139.63 : 209.31 = 112.42 : x
2. Step 2: Convert to fraction form
   139.63/209.31 = 112.42/x
3. Step 3: Cross multiply
   139.63x = 209.31 × 112.42
4. Step 4: Simplify right side
   139.63x = 23,530.63
5. Step 5: Solve for x
   x = 23,530.63/139.63
6. Step 6: Final answer
   x = 168.52