Finding the Fourth Proportional to 1,307.71, 1,960.20 and 485.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,307.71 : 1,960.20 = 485.61 : x
2. Step 2: Convert to fraction form
   1,307.71/1,960.20 = 485.61/x
3. Step 3: Cross multiply
   1,307.71x = 1,960.20 × 485.61
4. Step 4: Simplify right side
   1,307.71x = 951,892.72
5. Step 5: Solve for x
   x = 951,892.72/1,307.71
6. Step 6: Final answer
   x = 727.91