Finding the Fourth Proportional to 1,760.80, 2,431.90 and 1,200.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,760.80 : 2,431.90 = 1,200.31 : x
2. Step 2: Convert to fraction form
   1,760.80/2,431.90 = 1,200.31/x
3. Step 3: Cross multiply
   1,760.80x = 2,431.90 × 1,200.31
4. Step 4: Simplify right side
   1,760.80x = 2,919,015.73
5. Step 5: Solve for x
   x = 2,919,015.73/1,760.80
6. Step 6: Final answer
   x = 1,657.78