Finding the Fourth Proportional to 2,081.56, 3,121.98 and 782.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,081.56 : 3,121.98 = 782.80 : x
2. Step 2: Convert to fraction form
   2,081.56/3,121.98 = 782.80/x
3. Step 3: Cross multiply
   2,081.56x = 3,121.98 × 782.80
4. Step 4: Simplify right side
   2,081.56x = 2,443,885.94
5. Step 5: Solve for x
   x = 2,443,885.94/2,081.56
6. Step 6: Final answer
   x = 1,174.06