Finding the Fourth Proportional to 1,383.79, 1,909.08 and 1,288.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.79 : 1,909.08 = 1,288.71 : x
2. Step 2: Convert to fraction form
   1,383.79/1,909.08 = 1,288.71/x
3. Step 3: Cross multiply
   1,383.79x = 1,909.08 × 1,288.71
4. Step 4: Simplify right side
   1,383.79x = 2,460,250.49
5. Step 5: Solve for x
   x = 2,460,250.49/1,383.79
6. Step 6: Final answer
   x = 1,777.91