Finding the Fourth Proportional to 1,961.81, 2,940.86 and 728.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,961.81 : 2,940.86 = 728.39 : x
2. Step 2: Convert to fraction form
   1,961.81/2,940.86 = 728.39/x
3. Step 3: Cross multiply
   1,961.81x = 2,940.86 × 728.39
4. Step 4: Simplify right side
   1,961.81x = 2,142,078.31
5. Step 5: Solve for x
   x = 2,142,078.31/1,961.81
6. Step 6: Final answer
   x = 1,091.89