Finding the Fourth Proportional to 1,390.02, 1,918.18 and 800.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.02 : 1,918.18 = 800.54 : x
2. Step 2: Convert to fraction form
   1,390.02/1,918.18 = 800.54/x
3. Step 3: Cross multiply
   1,390.02x = 1,918.18 × 800.54
4. Step 4: Simplify right side
   1,390.02x = 1,535,579.82
5. Step 5: Solve for x
   x = 1,535,579.82/1,390.02
6. Step 6: Final answer
   x = 1,104.72