Finding the Fourth Proportional to 1,036.62, 1,428.89 and 815.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,036.62 : 1,428.89 = 815.28 : x
2. Step 2: Convert to fraction form
   1,036.62/1,428.89 = 815.28/x
3. Step 3: Cross multiply
   1,036.62x = 1,428.89 × 815.28
4. Step 4: Simplify right side
   1,036.62x = 1,164,941.36
5. Step 5: Solve for x
   x = 1,164,941.36/1,036.62
6. Step 6: Final answer
   x = 1,123.79