Finding the Fourth Proportional to 2,114.70, 3,171.69 and 815.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,114.70 : 3,171.69 = 815.10 : x
2. Step 2: Convert to fraction form
   2,114.70/3,171.69 = 815.10/x
3. Step 3: Cross multiply
   2,114.70x = 3,171.69 × 815.10
4. Step 4: Simplify right side
   2,114.70x = 2,585,244.52
5. Step 5: Solve for x
   x = 2,585,244.52/2,114.70
6. Step 6: Final answer
   x = 1,222.51