Finding the Third Proportional to 2,158.31 and 2,821.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,158.31 : 2,821.78 = 2,821.78 : x
2. Step 2: Convert to fraction form
   2,158.31/2,821.78 = 2,821.78/x
3. Step 3: Cross multiply
   2,158.31x = 2,821.78 × 2,821.78
4. Step 4: Simplify right side
   2,158.31x = 7,962,449.42
5. Step 5: Solve for x
   x = 7,962,449.42/2,158.31
6. Step 6: Final answer
   x = 3,689.20