Finding the Fourth Proportional to 105.34, 158.19 and 64.78

Step by Step Solution

1. Step 1: Write the proportion equation
   105.34 : 158.19 = 64.78 : x
2. Step 2: Convert to fraction form
   105.34/158.19 = 64.78/x
3. Step 3: Cross multiply
   105.34x = 158.19 × 64.78
4. Step 4: Simplify right side
   105.34x = 10,247.55
5. Step 5: Solve for x
   x = 10,247.55/105.34
6. Step 6: Final answer
   x = 97.28