Finding the Fourth Proportional to 1,389.27, 1,917.15 and 759.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.27 : 1,917.15 = 759.80 : x
2. Step 2: Convert to fraction form
   1,389.27/1,917.15 = 759.80/x
3. Step 3: Cross multiply
   1,389.27x = 1,917.15 × 759.80
4. Step 4: Simplify right side
   1,389.27x = 1,456,640.98
5. Step 5: Solve for x
   x = 1,456,640.98/1,389.27
6. Step 6: Final answer
   x = 1,048.49