Finding the Fourth Proportional to 2,570.79, 3,856.55 and 816.29

Step by Step Solution

1. Step 1: Write the proportion equation
   2,570.79 : 3,856.55 = 816.29 : x
2. Step 2: Convert to fraction form
   2,570.79/3,856.55 = 816.29/x
3. Step 3: Cross multiply
   2,570.79x = 3,856.55 × 816.29
4. Step 4: Simplify right side
   2,570.79x = 3,148,063.20
5. Step 5: Solve for x
   x = 3,148,063.20/2,570.79
6. Step 6: Final answer
   x = 1,224.55