Finding the Fourth Proportional to 72.78, 109.21 and 34.28

Step by Step Solution

1. Step 1: Write the proportion equation
   72.78 : 109.21 = 34.28 : x
2. Step 2: Convert to fraction form
   72.78/109.21 = 34.28/x
3. Step 3: Cross multiply
   72.78x = 109.21 × 34.28
4. Step 4: Simplify right side
   72.78x = 3,743.55
5. Step 5: Solve for x
   x = 3,743.55/72.78
6. Step 6: Final answer
   x = 51.44