Finding the Fourth Proportional to 1,311.73, 1,810.41 and 780.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.73 : 1,810.41 = 780.37 : x
2. Step 2: Convert to fraction form
   1,311.73/1,810.41 = 780.37/x
3. Step 3: Cross multiply
   1,311.73x = 1,810.41 × 780.37
4. Step 4: Simplify right side
   1,311.73x = 1,412,789.65
5. Step 5: Solve for x
   x = 1,412,789.65/1,311.73
6. Step 6: Final answer
   x = 1,077.04