Finding the Fourth Proportional to 1,216.89, 1,822.59 and 853.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.89 : 1,822.59 = 853.30 : x
2. Step 2: Convert to fraction form
   1,216.89/1,822.59 = 853.30/x
3. Step 3: Cross multiply
   1,216.89x = 1,822.59 × 853.30
4. Step 4: Simplify right side
   1,216.89x = 1,555,202.67
5. Step 5: Solve for x
   x = 1,555,202.67/1,216.89
6. Step 6: Final answer
   x = 1,278.02