Finding the Fourth Proportional to 1,383.75, 1,909.58 and 859.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.75 : 1,909.58 = 859.78 : x
2. Step 2: Convert to fraction form
   1,383.75/1,909.58 = 859.78/x
3. Step 3: Cross multiply
   1,383.75x = 1,909.58 × 859.78
4. Step 4: Simplify right side
   1,383.75x = 1,641,816.78
5. Step 5: Solve for x
   x = 1,641,816.78/1,383.75
6. Step 6: Final answer
   x = 1,186.50