Finding the Fourth Proportional to 1,387.24, 1,914.35 and 789.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.24 : 1,914.35 = 789.73 : x
2. Step 2: Convert to fraction form
   1,387.24/1,914.35 = 789.73/x
3. Step 3: Cross multiply
   1,387.24x = 1,914.35 × 789.73
4. Step 4: Simplify right side
   1,387.24x = 1,511,819.63
5. Step 5: Solve for x
   x = 1,511,819.63/1,387.24
6. Step 6: Final answer
   x = 1,089.80