Finding the Fourth Proportional to 2,145.91, 3,216.81 and 684.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,145.91 : 3,216.81 = 684.12 : x
2. Step 2: Convert to fraction form
   2,145.91/3,216.81 = 684.12/x
3. Step 3: Cross multiply
   2,145.91x = 3,216.81 × 684.12
4. Step 4: Simplify right side
   2,145.91x = 2,200,684.06
5. Step 5: Solve for x
   x = 2,200,684.06/2,145.91
6. Step 6: Final answer
   x = 1,025.52