Finding the Fourth Proportional to 143.47, 215.52 and 139.42

Step by Step Solution

1. Step 1: Write the proportion equation
   143.47 : 215.52 = 139.42 : x
2. Step 2: Convert to fraction form
   143.47/215.52 = 139.42/x
3. Step 3: Cross multiply
   143.47x = 215.52 × 139.42
4. Step 4: Simplify right side
   143.47x = 30,047.80
5. Step 5: Solve for x
   x = 30,047.80/143.47
6. Step 6: Final answer
   x = 209.44