Finding the Fourth Proportional to 105.80, 158.56 and 78.88

Step by Step Solution

1. Step 1: Write the proportion equation
   105.80 : 158.56 = 78.88 : x
2. Step 2: Convert to fraction form
   105.80/158.56 = 78.88/x
3. Step 3: Cross multiply
   105.80x = 158.56 × 78.88
4. Step 4: Simplify right side
   105.80x = 12,507.21
5. Step 5: Solve for x
   x = 12,507.21/105.80
6. Step 6: Final answer
   x = 118.22