Finding the Fourth Proportional to 2,570.84, 3,857.35 and 815.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2,570.84 : 3,857.35 = 815.98 : x
2. Step 2: Convert to fraction form
   2,570.84/3,857.35 = 815.98/x
3. Step 3: Cross multiply
   2,570.84x = 3,857.35 × 815.98
4. Step 4: Simplify right side
   2,570.84x = 3,147,520.45
5. Step 5: Solve for x
   x = 3,147,520.45/2,570.84
6. Step 6: Final answer
   x = 1,224.32