Finding the Fourth Proportional to 2,663.92, 3,995.61 and 815.05

Step by Step Solution

1. Step 1: Write the proportion equation
   2,663.92 : 3,995.61 = 815.05 : x
2. Step 2: Convert to fraction form
   2,663.92/3,995.61 = 815.05/x
3. Step 3: Cross multiply
   2,663.92x = 3,995.61 × 815.05
4. Step 4: Simplify right side
   2,663.92x = 3,256,621.93
5. Step 5: Solve for x
   x = 3,256,621.93/2,663.92
6. Step 6: Final answer
   x = 1,222.49