Finding the Fourth Proportional to 1,390.52, 1,918.80 and 800.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.52 : 1,918.80 = 800.96 : x
2. Step 2: Convert to fraction form
   1,390.52/1,918.80 = 800.96/x
3. Step 3: Cross multiply
   1,390.52x = 1,918.80 × 800.96
4. Step 4: Simplify right side
   1,390.52x = 1,536,882.05
5. Step 5: Solve for x
   x = 1,536,882.05/1,390.52
6. Step 6: Final answer
   x = 1,105.26