Finding the Fourth Proportional to 1,389.99, 1,918.22 and 800.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.99 : 1,918.22 = 800.49 : x
2. Step 2: Convert to fraction form
   1,389.99/1,918.22 = 800.49/x
3. Step 3: Cross multiply
   1,389.99x = 1,918.22 × 800.49
4. Step 4: Simplify right side
   1,389.99x = 1,535,515.93
5. Step 5: Solve for x
   x = 1,535,515.93/1,389.99
6. Step 6: Final answer
   x = 1,104.70