Finding the Fourth Proportional to 1,208.98, 1,668.52 and 685.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,208.98 : 1,668.52 = 685.05 : x
2. Step 2: Convert to fraction form
   1,208.98/1,668.52 = 685.05/x
3. Step 3: Cross multiply
   1,208.98x = 1,668.52 × 685.05
4. Step 4: Simplify right side
   1,208.98x = 1,143,019.63
5. Step 5: Solve for x
   x = 1,143,019.63/1,208.98
6. Step 6: Final answer
   x = 945.44