Finding the Fourth Proportional to 1,209.43, 1,667.67 and 789.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.43 : 1,667.67 = 789.63 : x
2. Step 2: Convert to fraction form
   1,209.43/1,667.67 = 789.63/x
3. Step 3: Cross multiply
   1,209.43x = 1,667.67 × 789.63
4. Step 4: Simplify right side
   1,209.43x = 1,316,838.91
5. Step 5: Solve for x
   x = 1,316,838.91/1,209.43
6. Step 6: Final answer
   x = 1,088.81