Finding the Fourth Proportional to 1,099.89, 1,517.90 and 820.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,099.89 : 1,517.90 = 820.88 : x
2. Step 2: Convert to fraction form
   1,099.89/1,517.90 = 820.88/x
3. Step 3: Cross multiply
   1,099.89x = 1,517.90 × 820.88
4. Step 4: Simplify right side
   1,099.89x = 1,246,002.06
5. Step 5: Solve for x
   x = 1,246,002.06/1,099.89
6. Step 6: Final answer
   x = 1,132.84