Finding the Fourth Proportional to 2,086.15, 3,128.09 and 914.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.15 : 3,128.09 = 914.78 : x
2. Step 2: Convert to fraction form
   2,086.15/3,128.09 = 914.78/x
3. Step 3: Cross multiply
   2,086.15x = 3,128.09 × 914.78
4. Step 4: Simplify right side
   2,086.15x = 2,861,520.74
5. Step 5: Solve for x
   x = 2,861,520.74/2,086.15
6. Step 6: Final answer
   x = 1,371.68