Finding the Fourth Proportional to 123.42, 185.06 and 105.15

Step by Step Solution

1. Step 1: Write the proportion equation
   123.42 : 185.06 = 105.15 : x
2. Step 2: Convert to fraction form
   123.42/185.06 = 105.15/x
3. Step 3: Cross multiply
   123.42x = 185.06 × 105.15
4. Step 4: Simplify right side
   123.42x = 19,458.53
5. Step 5: Solve for x
   x = 19,458.53/123.42
6. Step 6: Final answer
   x = 157.66