Finding the Fourth Proportional to 1,439.72, 1,987.77 and 1,107.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.72 : 1,987.77 = 1,107.56 : x
2. Step 2: Convert to fraction form
   1,439.72/1,987.77 = 1,107.56/x
3. Step 3: Cross multiply
   1,439.72x = 1,987.77 × 1,107.56
4. Step 4: Simplify right side
   1,439.72x = 2,201,574.54
5. Step 5: Solve for x
   x = 2,201,574.54/1,439.72
6. Step 6: Final answer
   x = 1,529.17