Finding the Fourth Proportional to 105.84, 158.78 and 64.78

Step by Step Solution

1. Step 1: Write the proportion equation
   105.84 : 158.78 = 64.78 : x
2. Step 2: Convert to fraction form
   105.84/158.78 = 64.78/x
3. Step 3: Cross multiply
   105.84x = 158.78 × 64.78
4. Step 4: Simplify right side
   105.84x = 10,285.77
5. Step 5: Solve for x
   x = 10,285.77/105.84
6. Step 6: Final answer
   x = 97.18