Finding the Fourth Proportional to 1,390.29, 1,918.04 and 918.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.29 : 1,918.04 = 918.43 : x
2. Step 2: Convert to fraction form
   1,390.29/1,918.04 = 918.43/x
3. Step 3: Cross multiply
   1,390.29x = 1,918.04 × 918.43
4. Step 4: Simplify right side
   1,390.29x = 1,761,585.48
5. Step 5: Solve for x
   x = 1,761,585.48/1,390.29
6. Step 6: Final answer
   x = 1,267.06