Finding the Fourth Proportional to 1,391.83, 1,919.89 and 867.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.83 : 1,919.89 = 867.76 : x
2. Step 2: Convert to fraction form
   1,391.83/1,919.89 = 867.76/x
3. Step 3: Cross multiply
   1,391.83x = 1,919.89 × 867.76
4. Step 4: Simplify right side
   1,391.83x = 1,666,003.75
5. Step 5: Solve for x
   x = 1,666,003.75/1,391.83
6. Step 6: Final answer
   x = 1,196.99