Finding the Fourth Proportional to 1,139.15, 1,572.39 and 1,026.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.15 : 1,572.39 = 1,026.42 : x
2. Step 2: Convert to fraction form
   1,139.15/1,572.39 = 1,026.42/x
3. Step 3: Cross multiply
   1,139.15x = 1,572.39 × 1,026.42
4. Step 4: Simplify right side
   1,139.15x = 1,613,932.54
5. Step 5: Solve for x
   x = 1,613,932.54/1,139.15
6. Step 6: Final answer
   x = 1,416.79