Finding the Fourth Proportional to 1,209.65, 1,669.37 and 712.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.65 : 1,669.37 = 712.31 : x
2. Step 2: Convert to fraction form
   1,209.65/1,669.37 = 712.31/x
3. Step 3: Cross multiply
   1,209.65x = 1,669.37 × 712.31
4. Step 4: Simplify right side
   1,209.65x = 1,189,097.04
5. Step 5: Solve for x
   x = 1,189,097.04/1,209.65
6. Step 6: Final answer
   x = 983.01