Finding the Fourth Proportional to 127.89, 176.42 and 78.75

Step by Step Solution

1. Step 1: Write the proportion equation
   127.89 : 176.42 = 78.75 : x
2. Step 2: Convert to fraction form
   127.89/176.42 = 78.75/x
3. Step 3: Cross multiply
   127.89x = 176.42 × 78.75
4. Step 4: Simplify right side
   127.89x = 13,892.68
5. Step 5: Solve for x
   x = 13,892.68/127.89
6. Step 6: Final answer
   x = 108.63