Finding the Fourth Proportional to 2,145.93, 3,218.79 and 685.02

Step by Step Solution

1. Step 1: Write the proportion equation
   2,145.93 : 3,218.79 = 685.02 : x
2. Step 2: Convert to fraction form
   2,145.93/3,218.79 = 685.02/x
3. Step 3: Cross multiply
   2,145.93x = 3,218.79 × 685.02
4. Step 4: Simplify right side
   2,145.93x = 2,204,935.53
5. Step 5: Solve for x
   x = 2,204,935.53/2,145.93
6. Step 6: Final answer
   x = 1,027.50