Finding the Fourth Proportional to 1,339.40, 1,848.34 and 815.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.40 : 1,848.34 = 815.56 : x
2. Step 2: Convert to fraction form
   1,339.40/1,848.34 = 815.56/x
3. Step 3: Cross multiply
   1,339.40x = 1,848.34 × 815.56
4. Step 4: Simplify right side
   1,339.40x = 1,507,432.17
5. Step 5: Solve for x
   x = 1,507,432.17/1,339.40
6. Step 6: Final answer
   x = 1,125.45