Finding the Fourth Proportional to 1,304.86, 1,801.16 and 780.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,304.86 : 1,801.16 = 780.89 : x
2. Step 2: Convert to fraction form
   1,304.86/1,801.16 = 780.89/x
3. Step 3: Cross multiply
   1,304.86x = 1,801.16 × 780.89
4. Step 4: Simplify right side
   1,304.86x = 1,406,510.18
5. Step 5: Solve for x
   x = 1,406,510.18/1,304.86
6. Step 6: Final answer
   x = 1,077.90