Finding the Fourth Proportional to 1,390.38, 1,918.72 and 769.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.38 : 1,918.72 = 769.38 : x
2. Step 2: Convert to fraction form
   1,390.38/1,918.72 = 769.38/x
3. Step 3: Cross multiply
   1,390.38x = 1,918.72 × 769.38
4. Step 4: Simplify right side
   1,390.38x = 1,476,224.79
5. Step 5: Solve for x
   x = 1,476,224.79/1,390.38
6. Step 6: Final answer
   x = 1,061.74