Finding the Fourth Proportional to 1,275.89, 1,906.09 and 809.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,275.89 : 1,906.09 = 809.94 : x
2. Step 2: Convert to fraction form
   1,275.89/1,906.09 = 809.94/x
3. Step 3: Cross multiply
   1,275.89x = 1,906.09 × 809.94
4. Step 4: Simplify right side
   1,275.89x = 1,543,816.51
5. Step 5: Solve for x
   x = 1,543,816.51/1,275.89
6. Step 6: Final answer
   x = 1,209.99