Finding the Fourth Proportional to 2,287.91, 3,157.31 and 1,239.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2,287.91 : 3,157.31 = 1,239.98 : x
2. Step 2: Convert to fraction form
   2,287.91/3,157.31 = 1,239.98/x
3. Step 3: Cross multiply
   2,287.91x = 3,157.31 × 1,239.98
4. Step 4: Simplify right side
   2,287.91x = 3,914,985.47
5. Step 5: Solve for x
   x = 3,914,985.47/2,287.91
6. Step 6: Final answer
   x = 1,711.16