Finding the Fourth Proportional to 2,114.48, 3,171.78 and 815.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,114.48 : 3,171.78 = 815.76 : x
2. Step 2: Convert to fraction form
   2,114.48/3,171.78 = 815.76/x
3. Step 3: Cross multiply
   2,114.48x = 3,171.78 × 815.76
4. Step 4: Simplify right side
   2,114.48x = 2,587,411.25
5. Step 5: Solve for x
   x = 2,587,411.25/2,114.48
6. Step 6: Final answer
   x = 1,223.66