Finding the Fourth Proportional to 2,115.72, 3,174.12 and 817.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,115.72 : 3,174.12 = 817.56 : x
2. Step 2: Convert to fraction form
   2,115.72/3,174.12 = 817.56/x
3. Step 3: Cross multiply
   2,115.72x = 3,174.12 × 817.56
4. Step 4: Simplify right side
   2,115.72x = 2,595,033.55
5. Step 5: Solve for x
   x = 2,595,033.55/2,115.72
6. Step 6: Final answer
   x = 1,226.55