Finding the Fourth Proportional to 1,278.07, 1,763.61 and 780.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,278.07 : 1,763.61 = 780.83 : x
2. Step 2: Convert to fraction form
   1,278.07/1,763.61 = 780.83/x
3. Step 3: Cross multiply
   1,278.07x = 1,763.61 × 780.83
4. Step 4: Simplify right side
   1,278.07x = 1,377,075.69
5. Step 5: Solve for x
   x = 1,377,075.69/1,278.07
6. Step 6: Final answer
   x = 1,077.46