Finding the Fourth Proportional to 1,426.38, 2,139.56 and 768.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,426.38 : 2,139.56 = 768.57 : x
2. Step 2: Convert to fraction form
   1,426.38/2,139.56 = 768.57/x
3. Step 3: Cross multiply
   1,426.38x = 2,139.56 × 768.57
4. Step 4: Simplify right side
   1,426.38x = 1,644,387.09
5. Step 5: Solve for x
   x = 1,644,387.09/1,426.38
6. Step 6: Final answer
   x = 1,152.84