Finding the Fourth Proportional to 123.98, 185.72 and 105.78

Step by Step Solution

1. Step 1: Write the proportion equation
   123.98 : 185.72 = 105.78 : x
2. Step 2: Convert to fraction form
   123.98/185.72 = 105.78/x
3. Step 3: Cross multiply
   123.98x = 185.72 × 105.78
4. Step 4: Simplify right side
   123.98x = 19,645.40
5. Step 5: Solve for x
   x = 19,645.40/123.98
6. Step 6: Final answer
   x = 158.46