Finding the Fourth Proportional to 139.77, 209.69 and 42.27

Step by Step Solution

1. Step 1: Write the proportion equation
   139.77 : 209.69 = 42.27 : x
2. Step 2: Convert to fraction form
   139.77/209.69 = 42.27/x
3. Step 3: Cross multiply
   139.77x = 209.69 × 42.27
4. Step 4: Simplify right side
   139.77x = 8,863.38
5. Step 5: Solve for x
   x = 8,863.38/139.77
6. Step 6: Final answer
   x = 63.41