Finding the Fourth Proportional to 1,456.38, 2,185.31 and 840.65

Step by Step Solution

1. Step 1: Write the proportion equation
   1,456.38 : 2,185.31 = 840.65 : x
2. Step 2: Convert to fraction form
   1,456.38/2,185.31 = 840.65/x
3. Step 3: Cross multiply
   1,456.38x = 2,185.31 × 840.65
4. Step 4: Simplify right side
   1,456.38x = 1,837,072.03
5. Step 5: Solve for x
   x = 1,837,072.03/1,456.38
6. Step 6: Final answer
   x = 1,261.40