Finding the Fourth Proportional to 2,287.25, 3,156.17 and 1,278.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,287.25 : 3,156.17 = 1,278.90 : x
2. Step 2: Convert to fraction form
   2,287.25/3,156.17 = 1,278.90/x
3. Step 3: Cross multiply
   2,287.25x = 3,156.17 × 1,278.90
4. Step 4: Simplify right side
   2,287.25x = 4,036,419.42
5. Step 5: Solve for x
   x = 4,036,419.42/2,287.25
6. Step 6: Final answer
   x = 1,764.75