Finding the Fourth Proportional to 1,371.78, 2,057.40 and 1,142.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,371.78 : 2,057.40 = 1,142.15 : x
2. Step 2: Convert to fraction form
   1,371.78/2,057.40 = 1,142.15/x
3. Step 3: Cross multiply
   1,371.78x = 2,057.40 × 1,142.15
4. Step 4: Simplify right side
   1,371.78x = 2,349,849.12
5. Step 5: Solve for x
   x = 2,349,849.12/1,371.78
6. Step 6: Final answer
   x = 1,712.99