Finding the Fourth Proportional to 1,383.91, 1,910.30 and 918.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.91 : 1,910.30 = 918.31 : x
2. Step 2: Convert to fraction form
   1,383.91/1,910.30 = 918.31/x
3. Step 3: Cross multiply
   1,383.91x = 1,910.30 × 918.31
4. Step 4: Simplify right side
   1,383.91x = 1,754,247.59
5. Step 5: Solve for x
   x = 1,754,247.59/1,383.91
6. Step 6: Final answer
   x = 1,267.60