Finding the Fourth Proportional to 1,389.99, 1,918.06 and 800.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.99 : 1,918.06 = 800.56 : x
2. Step 2: Convert to fraction form
   1,389.99/1,918.06 = 800.56/x
3. Step 3: Cross multiply
   1,389.99x = 1,918.06 × 800.56
4. Step 4: Simplify right side
   1,389.99x = 1,535,522.11
5. Step 5: Solve for x
   x = 1,535,522.11/1,389.99
6. Step 6: Final answer
   x = 1,104.70