Finding the Fourth Proportional to 2,145.69, 3,216.49 and 683.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,145.69 : 3,216.49 = 683.90 : x
2. Step 2: Convert to fraction form
   2,145.69/3,216.49 = 683.90/x
3. Step 3: Cross multiply
   2,145.69x = 3,216.49 × 683.90
4. Step 4: Simplify right side
   2,145.69x = 2,199,757.51
5. Step 5: Solve for x
   x = 2,199,757.51/2,145.69
6. Step 6: Final answer
   x = 1,025.20