Finding the Fourth Proportional to 1,339.56, 1,848.60 and 815.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.56 : 1,848.60 = 815.28 : x
2. Step 2: Convert to fraction form
   1,339.56/1,848.60 = 815.28/x
3. Step 3: Cross multiply
   1,339.56x = 1,848.60 × 815.28
4. Step 4: Simplify right side
   1,339.56x = 1,507,126.61
5. Step 5: Solve for x
   x = 1,507,126.61/1,339.56
6. Step 6: Final answer
   x = 1,125.09