Finding the Fourth Proportional to 2,800.72, 4,201.98 and 853.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,800.72 : 4,201.98 = 853.30 : x
2. Step 2: Convert to fraction form
   2,800.72/4,201.98 = 853.30/x
3. Step 3: Cross multiply
   2,800.72x = 4,201.98 × 853.30
4. Step 4: Simplify right side
   2,800.72x = 3,585,549.53
5. Step 5: Solve for x
   x = 3,585,549.53/2,800.72
6. Step 6: Final answer
   x = 1,280.22