Finding the Fourth Proportional to 224.72, 337.20 and 128.72

Step by Step Solution

1. Step 1: Write the proportion equation
   224.72 : 337.20 = 128.72 : x
2. Step 2: Convert to fraction form
   224.72/337.20 = 128.72/x
3. Step 3: Cross multiply
   224.72x = 337.20 × 128.72
4. Step 4: Simplify right side
   224.72x = 43,404.38
5. Step 5: Solve for x
   x = 43,404.38/224.72
6. Step 6: Final answer
   x = 193.15