Finding the Fourth Proportional to 2,809.12, 4,211.28 and 1,420.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,809.12 : 4,211.28 = 1,420.72 : x
2. Step 2: Convert to fraction form
   2,809.12/4,211.28 = 1,420.72/x
3. Step 3: Cross multiply
   2,809.12x = 4,211.28 × 1,420.72
4. Step 4: Simplify right side
   2,809.12x = 5,983,049.72
5. Step 5: Solve for x
   x = 5,983,049.72/2,809.12
6. Step 6: Final answer
   x = 2,129.87