Finding the Fourth Proportional to 1,478.36, 2,040.17 and 815.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,478.36 : 2,040.17 = 815.20 : x
2. Step 2: Convert to fraction form
   1,478.36/2,040.17 = 815.20/x
3. Step 3: Cross multiply
   1,478.36x = 2,040.17 × 815.20
4. Step 4: Simplify right side
   1,478.36x = 1,663,137.41
5. Step 5: Solve for x
   x = 1,663,137.41/1,478.36
6. Step 6: Final answer
   x = 1,124.99