Finding the Fourth Proportional to 1,915.55, 2,871.23 and 820.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,915.55 : 2,871.23 = 820.56 : x
2. Step 2: Convert to fraction form
   1,915.55/2,871.23 = 820.56/x
3. Step 3: Cross multiply
   1,915.55x = 2,871.23 × 820.56
4. Step 4: Simplify right side
   1,915.55x = 2,356,012.39
5. Step 5: Solve for x
   x = 2,356,012.39/1,915.55
6. Step 6: Final answer
   x = 1,229.94