Finding the Fourth Proportional to 1,205.21, 1,662.89 and 681.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,205.21 : 1,662.89 = 681.23 : x
2. Step 2: Convert to fraction form
   1,205.21/1,662.89 = 681.23/x
3. Step 3: Cross multiply
   1,205.21x = 1,662.89 × 681.23
4. Step 4: Simplify right side
   1,205.21x = 1,132,798.83
5. Step 5: Solve for x
   x = 1,132,798.83/1,205.21
6. Step 6: Final answer
   x = 939.92