Finding the Fourth Proportional to 1,389.43, 1,917.41 and 768.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.43 : 1,917.41 = 768.43 : x
2. Step 2: Convert to fraction form
   1,389.43/1,917.41 = 768.43/x
3. Step 3: Cross multiply
   1,389.43x = 1,917.41 × 768.43
4. Step 4: Simplify right side
   1,389.43x = 1,473,386.73
5. Step 5: Solve for x
   x = 1,473,386.73/1,389.43
6. Step 6: Final answer
   x = 1,060.43