Finding the Fourth Proportional to 1,390.57, 1,918.41 and 919.00

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.57 : 1,918.41 = 919.00 : x
2. Step 2: Convert to fraction form
   1,390.57/1,918.41 = 919.00/x
3. Step 3: Cross multiply
   1,390.57x = 1,918.41 × 919.00
4. Step 4: Simplify right side
   1,390.57x = 1,763,009.54
5. Step 5: Solve for x
   x = 1,763,009.54/1,390.57
6. Step 6: Final answer
   x = 1,267.83