Finding the Fourth Proportional to 1,209.83, 1,668.89 and 712.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.83 : 1,668.89 = 712.40 : x
2. Step 2: Convert to fraction form
   1,209.83/1,668.89 = 712.40/x
3. Step 3: Cross multiply
   1,209.83x = 1,668.89 × 712.40
4. Step 4: Simplify right side
   1,209.83x = 1,188,905.33
5. Step 5: Solve for x
   x = 1,188,905.33/1,209.83
6. Step 6: Final answer
   x = 982.71