Finding the Fourth Proportional to 139.67, 209.49 and 42.17

Step by Step Solution

1. Step 1: Write the proportion equation
   139.67 : 209.49 = 42.17 : x
2. Step 2: Convert to fraction form
   139.67/209.49 = 42.17/x
3. Step 3: Cross multiply
   139.67x = 209.49 × 42.17
4. Step 4: Simplify right side
   139.67x = 8,834.17
5. Step 5: Solve for x
   x = 8,834.17/139.67
6. Step 6: Final answer
   x = 63.25