Finding the Fourth Proportional to 1,227.30, 1,837.79 and 815.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,227.30 : 1,837.79 = 815.15 : x
2. Step 2: Convert to fraction form
   1,227.30/1,837.79 = 815.15/x
3. Step 3: Cross multiply
   1,227.30x = 1,837.79 × 815.15
4. Step 4: Simplify right side
   1,227.30x = 1,498,061.25
5. Step 5: Solve for x
   x = 1,498,061.25/1,227.30
6. Step 6: Final answer
   x = 1,220.62