Finding the Fourth Proportional to 1,395.12, 2,091.78 and 810.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,395.12 : 2,091.78 = 810.24 : x
2. Step 2: Convert to fraction form
   1,395.12/2,091.78 = 810.24/x
3. Step 3: Cross multiply
   1,395.12x = 2,091.78 × 810.24
4. Step 4: Simplify right side
   1,395.12x = 1,694,843.83
5. Step 5: Solve for x
   x = 1,694,843.83/1,395.12
6. Step 6: Final answer
   x = 1,214.84