Finding the Fourth Proportional to 1,209.30, 1,668.72 and 678.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.30 : 1,668.72 = 678.25 : x
2. Step 2: Convert to fraction form
   1,209.30/1,668.72 = 678.25/x
3. Step 3: Cross multiply
   1,209.30x = 1,668.72 × 678.25
4. Step 4: Simplify right side
   1,209.30x = 1,131,809.34
5. Step 5: Solve for x
   x = 1,131,809.34/1,209.30
6. Step 6: Final answer
   x = 935.92