Finding the Fourth Proportional to 1,380.47, 2,067.71 and 860.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.47 : 2,067.71 = 860.58 : x
2. Step 2: Convert to fraction form
   1,380.47/2,067.71 = 860.58/x
3. Step 3: Cross multiply
   1,380.47x = 2,067.71 × 860.58
4. Step 4: Simplify right side
   1,380.47x = 1,779,425.57
5. Step 5: Solve for x
   x = 1,779,425.57/1,380.47
6. Step 6: Final answer
   x = 1,289.00