Finding the Fourth Proportional to 1,478.27, 2,039.81 and 815.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,478.27 : 2,039.81 = 815.15 : x
2. Step 2: Convert to fraction form
   1,478.27/2,039.81 = 815.15/x
3. Step 3: Cross multiply
   1,478.27x = 2,039.81 × 815.15
4. Step 4: Simplify right side
   1,478.27x = 1,662,736.85
5. Step 5: Solve for x
   x = 1,662,736.85/1,478.27
6. Step 6: Final answer
   x = 1,124.79