Finding the Fourth Proportional to 1,339.64, 1,848.90 and 815.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.64 : 1,848.90 = 815.57 : x
2. Step 2: Convert to fraction form
   1,339.64/1,848.90 = 815.57/x
3. Step 3: Cross multiply
   1,339.64x = 1,848.90 × 815.57
4. Step 4: Simplify right side
   1,339.64x = 1,507,907.37
5. Step 5: Solve for x
   x = 1,507,907.37/1,339.64
6. Step 6: Final answer
   x = 1,125.61