Finding the Fourth Proportional to 1,439.88, 1,978.41 and 1,144.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.88 : 1,978.41 = 1,144.63 : x
2. Step 2: Convert to fraction form
   1,439.88/1,978.41 = 1,144.63/x
3. Step 3: Cross multiply
   1,439.88x = 1,978.41 × 1,144.63
4. Step 4: Simplify right side
   1,439.88x = 2,264,550.30
5. Step 5: Solve for x
   x = 2,264,550.30/1,439.88
6. Step 6: Final answer
   x = 1,572.74