Finding the Fourth Proportional to 1,287.84, 1,928.76 and 940.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.84 : 1,928.76 = 940.31 : x
2. Step 2: Convert to fraction form
   1,287.84/1,928.76 = 940.31/x
3. Step 3: Cross multiply
   1,287.84x = 1,928.76 × 940.31
4. Step 4: Simplify right side
   1,287.84x = 1,813,631.82
5. Step 5: Solve for x
   x = 1,813,631.82/1,287.84
6. Step 6: Final answer
   x = 1,408.27