Finding the Fourth Proportional to 1,206.65, 1,665.23 and 709.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,206.65 : 1,665.23 = 709.31 : x
2. Step 2: Convert to fraction form
   1,206.65/1,665.23 = 709.31/x
3. Step 3: Cross multiply
   1,206.65x = 1,665.23 × 709.31
4. Step 4: Simplify right side
   1,206.65x = 1,181,152.42
5. Step 5: Solve for x
   x = 1,181,152.42/1,206.65
6. Step 6: Final answer
   x = 978.87