Finding the Fourth Proportional to 1,906.80, 2,857.89 and 867.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,906.80 : 2,857.89 = 867.30 : x
2. Step 2: Convert to fraction form
   1,906.80/2,857.89 = 867.30/x
3. Step 3: Cross multiply
   1,906.80x = 2,857.89 × 867.30
4. Step 4: Simplify right side
   1,906.80x = 2,478,648.00
5. Step 5: Solve for x
   x = 2,478,648.00/1,906.80
6. Step 6: Final answer
   x = 1,299.90