Finding the Fourth Proportional to 1,786.21, 2,680.42 and 861.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,786.21 : 2,680.42 = 861.86 : x
2. Step 2: Convert to fraction form
   1,786.21/2,680.42 = 861.86/x
3. Step 3: Cross multiply
   1,786.21x = 2,680.42 × 861.86
4. Step 4: Simplify right side
   1,786.21x = 2,310,146.78
5. Step 5: Solve for x
   x = 2,310,146.78/1,786.21
6. Step 6: Final answer
   x = 1,293.32