Finding the Fourth Proportional to 1,389.65, 1,917.59 and 800.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.65 : 1,917.59 = 800.10 : x
2. Step 2: Convert to fraction form
   1,389.65/1,917.59 = 800.10/x
3. Step 3: Cross multiply
   1,389.65x = 1,917.59 × 800.10
4. Step 4: Simplify right side
   1,389.65x = 1,534,259.76
5. Step 5: Solve for x
   x = 1,534,259.76/1,389.65
6. Step 6: Final answer
   x = 1,104.07