Finding the Fourth Proportional to 2,013.31, 3,019.69 and 780.60

Step by Step Solution

1. Step 1: Write the proportion equation
   2,013.31 : 3,019.69 = 780.60 : x
2. Step 2: Convert to fraction form
   2,013.31/3,019.69 = 780.60/x
3. Step 3: Cross multiply
   2,013.31x = 3,019.69 × 780.60
4. Step 4: Simplify right side
   2,013.31x = 2,357,170.01
5. Step 5: Solve for x
   x = 2,357,170.01/2,013.31
6. Step 6: Final answer
   x = 1,170.79