Finding the Fourth Proportional to 1,442.56, 1,990.72 and 821.44

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.56 : 1,990.72 = 821.44 : x
2. Step 2: Convert to fraction form
   1,442.56/1,990.72 = 821.44/x
3. Step 3: Cross multiply
   1,442.56x = 1,990.72 × 821.44
4. Step 4: Simplify right side
   1,442.56x = 1,635,257.04
5. Step 5: Solve for x
   x = 1,635,257.04/1,442.56
6. Step 6: Final answer
   x = 1,133.58