Finding the Fourth Proportional to 1,389.72, 1,917.76 and 800.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.72 : 1,917.76 = 800.36 : x
2. Step 2: Convert to fraction form
   1,389.72/1,917.76 = 800.36/x
3. Step 3: Cross multiply
   1,389.72x = 1,917.76 × 800.36
4. Step 4: Simplify right side
   1,389.72x = 1,534,898.39
5. Step 5: Solve for x
   x = 1,534,898.39/1,389.72
6. Step 6: Final answer
   x = 1,104.47