Finding the Fourth Proportional to 2,570.86, 3,857.15 and 816.15

Step by Step Solution

1. Step 1: Write the proportion equation
   2,570.86 : 3,857.15 = 816.15 : x
2. Step 2: Convert to fraction form
   2,570.86/3,857.15 = 816.15/x
3. Step 3: Cross multiply
   2,570.86x = 3,857.15 × 816.15
4. Step 4: Simplify right side
   2,570.86x = 3,148,029.48
5. Step 5: Solve for x
   x = 3,148,029.48/2,570.86
6. Step 6: Final answer
   x = 1,224.50