Finding the Fourth Proportional to 2,570.42, 3,854.16 and 815.09

Step by Step Solution

1. Step 1: Write the proportion equation
   2,570.42 : 3,854.16 = 815.09 : x
2. Step 2: Convert to fraction form
   2,570.42/3,854.16 = 815.09/x
3. Step 3: Cross multiply
   2,570.42x = 3,854.16 × 815.09
4. Step 4: Simplify right side
   2,570.42x = 3,141,468.00
5. Step 5: Solve for x
   x = 3,141,468.00/2,570.42
6. Step 6: Final answer
   x = 1,222.16