Finding the Fourth Proportional to 139.38, 209.18 and 48.16

Step by Step Solution

1. Step 1: Write the proportion equation
   139.38 : 209.18 = 48.16 : x
2. Step 2: Convert to fraction form
   139.38/209.18 = 48.16/x
3. Step 3: Cross multiply
   139.38x = 209.18 × 48.16
4. Step 4: Simplify right side
   139.38x = 10,072.82
5. Step 5: Solve for x
   x = 10,072.82/139.38
6. Step 6: Final answer
   x = 72.27