Finding the Fourth Proportional to 1,362.72, 2,039.04 and 815.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,362.72 : 2,039.04 = 815.28 : x
2. Step 2: Convert to fraction form
   1,362.72/2,039.04 = 815.28/x
3. Step 3: Cross multiply
   1,362.72x = 2,039.04 × 815.28
4. Step 4: Simplify right side
   1,362.72x = 1,662,388.53
5. Step 5: Solve for x
   x = 1,662,388.53/1,362.72
6. Step 6: Final answer
   x = 1,219.90