Finding the Fourth Proportional to 1,273.20, 1,908.56 and 406.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,273.20 : 1,908.56 = 406.88 : x
2. Step 2: Convert to fraction form
   1,273.20/1,908.56 = 406.88/x
3. Step 3: Cross multiply
   1,273.20x = 1,908.56 × 406.88
4. Step 4: Simplify right side
   1,273.20x = 776,554.89
5. Step 5: Solve for x
   x = 776,554.89/1,273.20
6. Step 6: Final answer
   x = 609.92