Finding the Fourth Proportional to 1,578.98, 2,179.09 and 870.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,578.98 : 2,179.09 = 870.82 : x
2. Step 2: Convert to fraction form
   1,578.98/2,179.09 = 870.82/x
3. Step 3: Cross multiply
   1,578.98x = 2,179.09 × 870.82
4. Step 4: Simplify right side
   1,578.98x = 1,897,595.15
5. Step 5: Solve for x
   x = 1,897,595.15/1,578.98
6. Step 6: Final answer
   x = 1,201.79