Finding the Fourth Proportional to 1,659.40, 2,488.90 and 685.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,659.40 : 2,488.90 = 685.38 : x
2. Step 2: Convert to fraction form
   1,659.40/2,488.90 = 685.38/x
3. Step 3: Cross multiply
   1,659.40x = 2,488.90 × 685.38
4. Step 4: Simplify right side
   1,659.40x = 1,705,842.28
5. Step 5: Solve for x
   x = 1,705,842.28/1,659.40
6. Step 6: Final answer
   x = 1,027.99