Finding the Fourth Proportional to 1,439.47, 1,987.43 and 1,107.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.47 : 1,987.43 = 1,107.31 : x
2. Step 2: Convert to fraction form
   1,439.47/1,987.43 = 1,107.31/x
3. Step 3: Cross multiply
   1,439.47x = 1,987.43 × 1,107.31
4. Step 4: Simplify right side
   1,439.47x = 2,200,695.58
5. Step 5: Solve for x
   x = 2,200,695.58/1,439.47
6. Step 6: Final answer
   x = 1,528.82