Finding the Fourth Proportional to 123.78, 185.78 and 102.16

Step by Step Solution

1. Step 1: Write the proportion equation
   123.78 : 185.78 = 102.16 : x
2. Step 2: Convert to fraction form
   123.78/185.78 = 102.16/x
3. Step 3: Cross multiply
   123.78x = 185.78 × 102.16
4. Step 4: Simplify right side
   123.78x = 18,978.56
5. Step 5: Solve for x
   x = 18,978.56/123.78
6. Step 6: Final answer
   x = 153.32