Finding the Fourth Proportional to 105.90, 146.01 and 78.18

Step by Step Solution

1. Step 1: Write the proportion equation
   105.90 : 146.01 = 78.18 : x
2. Step 2: Convert to fraction form
   105.90/146.01 = 78.18/x
3. Step 3: Cross multiply
   105.90x = 146.01 × 78.18
4. Step 4: Simplify right side
   105.90x = 11,415.06
5. Step 5: Solve for x
   x = 11,415.06/105.90
6. Step 6: Final answer
   x = 107.79