Finding the Fourth Proportional to 92.78, 139.18 and 76.72

Step by Step Solution

1. Step 1: Write the proportion equation
   92.78 : 139.18 = 76.72 : x
2. Step 2: Convert to fraction form
   92.78/139.18 = 76.72/x
3. Step 3: Cross multiply
   92.78x = 139.18 × 76.72
4. Step 4: Simplify right side
   92.78x = 10,677.89
5. Step 5: Solve for x
   x = 10,677.89/92.78
6. Step 6: Final answer
   x = 115.09