Finding the Fourth Proportional to 2,810.38, 4,215.72 and 2,153.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,810.38 : 4,215.72 = 2,153.20 : x
2. Step 2: Convert to fraction form
   2,810.38/4,215.72 = 2,153.20/x
3. Step 3: Cross multiply
   2,810.38x = 4,215.72 × 2,153.20
4. Step 4: Simplify right side
   2,810.38x = 9,077,288.30
5. Step 5: Solve for x
   x = 9,077,288.30/2,810.38
6. Step 6: Final answer
   x = 3,229.91