Finding the Fourth Proportional to 1,439.78, 2,161.69 and 946.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.78 : 2,161.69 = 946.28 : x
2. Step 2: Convert to fraction form
   1,439.78/2,161.69 = 946.28/x
3. Step 3: Cross multiply
   1,439.78x = 2,161.69 × 946.28
4. Step 4: Simplify right side
   1,439.78x = 2,045,567.05
5. Step 5: Solve for x
   x = 2,045,567.05/1,439.78
6. Step 6: Final answer
   x = 1,420.75