Finding the Fourth Proportional to 1,382.65, 1,905.89 and 939.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,382.65 : 1,905.89 = 939.78 : x
2. Step 2: Convert to fraction form
   1,382.65/1,905.89 = 939.78/x
3. Step 3: Cross multiply
   1,382.65x = 1,905.89 × 939.78
4. Step 4: Simplify right side
   1,382.65x = 1,791,117.30
5. Step 5: Solve for x
   x = 1,791,117.30/1,382.65
6. Step 6: Final answer
   x = 1,295.42