Finding the Fourth Proportional to 139.95, 209.91 and 42.47

Step by Step Solution

1. Step 1: Write the proportion equation
   139.95 : 209.91 = 42.47 : x
2. Step 2: Convert to fraction form
   139.95/209.91 = 42.47/x
3. Step 3: Cross multiply
   139.95x = 209.91 × 42.47
4. Step 4: Simplify right side
   139.95x = 8,913.83
5. Step 5: Solve for x
   x = 8,913.83/139.95
6. Step 6: Final answer
   x = 63.69