Finding the Fourth Proportional to 2,663.89, 3,995.69 and 815.02

Step by Step Solution

1. Step 1: Write the proportion equation
   2,663.89 : 3,995.69 = 815.02 : x
2. Step 2: Convert to fraction form
   2,663.89/3,995.69 = 815.02/x
3. Step 3: Cross multiply
   2,663.89x = 3,995.69 × 815.02
4. Step 4: Simplify right side
   2,663.89x = 3,256,553.20
5. Step 5: Solve for x
   x = 3,256,553.20/2,663.89
6. Step 6: Final answer
   x = 1,222.48