Finding the Fourth Proportional to 105.60, 158.49 and 78.51

Step by Step Solution

1. Step 1: Write the proportion equation
   105.60 : 158.49 = 78.51 : x
2. Step 2: Convert to fraction form
   105.60/158.49 = 78.51/x
3. Step 3: Cross multiply
   105.60x = 158.49 × 78.51
4. Step 4: Simplify right side
   105.60x = 12,443.05
5. Step 5: Solve for x
   x = 12,443.05/105.60
6. Step 6: Final answer
   x = 117.83