Finding the Fourth Proportional to 1,288.05, 1,929.24 and 854.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.05 : 1,929.24 = 854.70 : x
2. Step 2: Convert to fraction form
   1,288.05/1,929.24 = 854.70/x
3. Step 3: Cross multiply
   1,288.05x = 1,929.24 × 854.70
4. Step 4: Simplify right side
   1,288.05x = 1,648,921.43
5. Step 5: Solve for x
   x = 1,648,921.43/1,288.05
6. Step 6: Final answer
   x = 1,280.17