Finding the Fourth Proportional to 139.71, 209.52 and 42.19

Step by Step Solution

1. Step 1: Write the proportion equation
   139.71 : 209.52 = 42.19 : x
2. Step 2: Convert to fraction form
   139.71/209.52 = 42.19/x
3. Step 3: Cross multiply
   139.71x = 209.52 × 42.19
4. Step 4: Simplify right side
   139.71x = 8,839.65
5. Step 5: Solve for x
   x = 8,839.65/139.71
6. Step 6: Final answer
   x = 63.27