Finding the Fourth Proportional to 2,872.10, 4,308.04 and 820.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,872.10 : 4,308.04 = 820.10 : x
2. Step 2: Convert to fraction form
   2,872.10/4,308.04 = 820.10/x
3. Step 3: Cross multiply
   2,872.10x = 4,308.04 × 820.10
4. Step 4: Simplify right side
   2,872.10x = 3,533,023.60
5. Step 5: Solve for x
   x = 3,533,023.60/2,872.10
6. Step 6: Final answer
   x = 1,230.12