Finding the Fourth Proportional to 1,909.52, 2,861.57 and 812.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,909.52 : 2,861.57 = 812.78 : x
2. Step 2: Convert to fraction form
   1,909.52/2,861.57 = 812.78/x
3. Step 3: Cross multiply
   1,909.52x = 2,861.57 × 812.78
4. Step 4: Simplify right side
   1,909.52x = 2,325,812.56
5. Step 5: Solve for x
   x = 2,325,812.56/1,909.52
6. Step 6: Final answer
   x = 1,218.01