Finding the Fourth Proportional to 105.43, 158.14 and 78.55

Step by Step Solution

1. Step 1: Write the proportion equation
   105.43 : 158.14 = 78.55 : x
2. Step 2: Convert to fraction form
   105.43/158.14 = 78.55/x
3. Step 3: Cross multiply
   105.43x = 158.14 × 78.55
4. Step 4: Simplify right side
   105.43x = 12,421.82
5. Step 5: Solve for x
   x = 12,421.82/105.43
6. Step 6: Final answer
   x = 117.82