Finding the Fourth Proportional to 105.78, 146.06 and 80.94

Step by Step Solution

1. Step 1: Write the proportion equation
   105.78 : 146.06 = 80.94 : x
2. Step 2: Convert to fraction form
   105.78/146.06 = 80.94/x
3. Step 3: Cross multiply
   105.78x = 146.06 × 80.94
4. Step 4: Simplify right side
   105.78x = 11,822.10
5. Step 5: Solve for x
   x = 11,822.10/105.78
6. Step 6: Final answer
   x = 111.76