Finding the Fourth Proportional to 1,379.30, 1,903.43 and 789.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.30 : 1,903.43 = 789.89 : x
2. Step 2: Convert to fraction form
   1,379.30/1,903.43 = 789.89/x
3. Step 3: Cross multiply
   1,379.30x = 1,903.43 × 789.89
4. Step 4: Simplify right side
   1,379.30x = 1,503,492.78
5. Step 5: Solve for x
   x = 1,503,492.78/1,379.30
6. Step 6: Final answer
   x = 1,090.04