Finding the Fourth Proportional to 1,439.30, 1,986.42 and 879.66

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.30 : 1,986.42 = 879.66 : x
2. Step 2: Convert to fraction form
   1,439.30/1,986.42 = 879.66/x
3. Step 3: Cross multiply
   1,439.30x = 1,986.42 × 879.66
4. Step 4: Simplify right side
   1,439.30x = 1,747,377.52
5. Step 5: Solve for x
   x = 1,747,377.52/1,439.30
6. Step 6: Final answer
   x = 1,214.04