Finding the Fourth Proportional to 1,288.96, 1,931.48 and 854.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.96 : 1,931.48 = 854.56 : x
2. Step 2: Convert to fraction form
   1,288.96/1,931.48 = 854.56/x
3. Step 3: Cross multiply
   1,288.96x = 1,931.48 × 854.56
4. Step 4: Simplify right side
   1,288.96x = 1,650,565.55
5. Step 5: Solve for x
   x = 1,650,565.55/1,288.96
6. Step 6: Final answer
   x = 1,280.54