Finding the Fourth Proportional to 123.78, 185.69 and 106.61

Step by Step Solution

1. Step 1: Write the proportion equation
   123.78 : 185.69 = 106.61 : x
2. Step 2: Convert to fraction form
   123.78/185.69 = 106.61/x
3. Step 3: Cross multiply
   123.78x = 185.69 × 106.61
4. Step 4: Simplify right side
   123.78x = 19,796.41
5. Step 5: Solve for x
   x = 19,796.41/123.78
6. Step 6: Final answer
   x = 159.93