Finding the Fourth Proportional to 1,309.12, 1,962.73 and 660.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,309.12 : 1,962.73 = 660.31 : x
2. Step 2: Convert to fraction form
   1,309.12/1,962.73 = 660.31/x
3. Step 3: Cross multiply
   1,309.12x = 1,962.73 × 660.31
4. Step 4: Simplify right side
   1,309.12x = 1,296,010.25
5. Step 5: Solve for x
   x = 1,296,010.25/1,309.12
6. Step 6: Final answer
   x = 989.99