Finding the Fourth Proportional to 2,743.20, 4,112.34 and 987.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,743.20 : 4,112.34 = 987.78 : x
2. Step 2: Convert to fraction form
   2,743.20/4,112.34 = 987.78/x
3. Step 3: Cross multiply
   2,743.20x = 4,112.34 × 987.78
4. Step 4: Simplify right side
   2,743.20x = 4,062,087.21
5. Step 5: Solve for x
   x = 4,062,087.21/2,743.20
6. Step 6: Final answer
   x = 1,480.78