Finding the Fourth Proportional to 127.72, 176.28 and 78.61

Step by Step Solution

1. Step 1: Write the proportion equation
   127.72 : 176.28 = 78.61 : x
2. Step 2: Convert to fraction form
   127.72/176.28 = 78.61/x
3. Step 3: Cross multiply
   127.72x = 176.28 × 78.61
4. Step 4: Simplify right side
   127.72x = 13,857.37
5. Step 5: Solve for x
   x = 13,857.37/127.72
6. Step 6: Final answer
   x = 108.50