Finding the Fourth Proportional to 1,391.28, 2,087.98 and 514.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.28 : 2,087.98 = 514.61 : x
2. Step 2: Convert to fraction form
   1,391.28/2,087.98 = 514.61/x
3. Step 3: Cross multiply
   1,391.28x = 2,087.98 × 514.61
4. Step 4: Simplify right side
   1,391.28x = 1,074,501.58
5. Step 5: Solve for x
   x = 1,074,501.58/1,391.28
6. Step 6: Final answer
   x = 772.31