Finding the Fourth Proportional to 105.65, 158.52 and 78.65

Step by Step Solution

1. Step 1: Write the proportion equation
   105.65 : 158.52 = 78.65 : x
2. Step 2: Convert to fraction form
   105.65/158.52 = 78.65/x
3. Step 3: Cross multiply
   105.65x = 158.52 × 78.65
4. Step 4: Simplify right side
   105.65x = 12,467.69
5. Step 5: Solve for x
   x = 12,467.69/105.65
6. Step 6: Final answer
   x = 118.01