Finding the Fourth Proportional to 1,390.08, 1,918.25 and 800.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.08 : 1,918.25 = 800.81 : x
2. Step 2: Convert to fraction form
   1,390.08/1,918.25 = 800.81/x
3. Step 3: Cross multiply
   1,390.08x = 1,918.25 × 800.81
4. Step 4: Simplify right side
   1,390.08x = 1,536,150.38
5. Step 5: Solve for x
   x = 1,536,150.38/1,390.08
6. Step 6: Final answer
   x = 1,105.08