Finding the Fourth Proportional to 2,379.39, 3,570.71 and 840.39

Step by Step Solution

1. Step 1: Write the proportion equation
   2,379.39 : 3,570.71 = 840.39 : x
2. Step 2: Convert to fraction form
   2,379.39/3,570.71 = 840.39/x
3. Step 3: Cross multiply
   2,379.39x = 3,570.71 × 840.39
4. Step 4: Simplify right side
   2,379.39x = 3,000,788.98
5. Step 5: Solve for x
   x = 3,000,788.98/2,379.39
6. Step 6: Final answer
   x = 1,261.16