Finding the Fourth Proportional to 1,395.05, 2,091.50 and 809.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,395.05 : 2,091.50 = 809.15 : x
2. Step 2: Convert to fraction form
   1,395.05/2,091.50 = 809.15/x
3. Step 3: Cross multiply
   1,395.05x = 2,091.50 × 809.15
4. Step 4: Simplify right side
   1,395.05x = 1,692,333.18
5. Step 5: Solve for x
   x = 1,692,333.18/1,395.05
6. Step 6: Final answer
   x = 1,213.10