Finding the Fourth Proportional to 2,565.05, 3,847.86 and 810.11

Step by Step Solution

1. Step 1: Write the proportion equation
   2,565.05 : 3,847.86 = 810.11 : x
2. Step 2: Convert to fraction form
   2,565.05/3,847.86 = 810.11/x
3. Step 3: Cross multiply
   2,565.05x = 3,847.86 × 810.11
4. Step 4: Simplify right side
   2,565.05x = 3,117,168.60
5. Step 5: Solve for x
   x = 3,117,168.60/2,565.05
6. Step 6: Final answer
   x = 1,215.25