Finding the Fourth Proportional to 1,208.86, 1,667.19 and 861.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,208.86 : 1,667.19 = 861.10 : x
2. Step 2: Convert to fraction form
   1,208.86/1,667.19 = 861.10/x
3. Step 3: Cross multiply
   1,208.86x = 1,667.19 × 861.10
4. Step 4: Simplify right side
   1,208.86x = 1,435,617.31
5. Step 5: Solve for x
   x = 1,435,617.31/1,208.86
6. Step 6: Final answer
   x = 1,187.58