Finding the Fourth Proportional to 2,664.72, 3,996.99 and 815.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,664.72 : 3,996.99 = 815.76 : x
2. Step 2: Convert to fraction form
   2,664.72/3,996.99 = 815.76/x
3. Step 3: Cross multiply
   2,664.72x = 3,996.99 × 815.76
4. Step 4: Simplify right side
   2,664.72x = 3,260,584.56
5. Step 5: Solve for x
   x = 3,260,584.56/2,664.72
6. Step 6: Final answer
   x = 1,223.61