Finding the Fourth Proportional to 1,287.34, 1,774.56 and 789.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.34 : 1,774.56 = 789.06 : x
2. Step 2: Convert to fraction form
   1,287.34/1,774.56 = 789.06/x
3. Step 3: Cross multiply
   1,287.34x = 1,774.56 × 789.06
4. Step 4: Simplify right side
   1,287.34x = 1,400,225.44
5. Step 5: Solve for x
   x = 1,400,225.44/1,287.34
6. Step 6: Final answer
   x = 1,087.69