Finding the Fourth Proportional to 2,287.80, 3,157.14 and 1,239.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,287.80 : 3,157.14 = 1,239.86 : x
2. Step 2: Convert to fraction form
   2,287.80/3,157.14 = 1,239.86/x
3. Step 3: Cross multiply
   2,287.80x = 3,157.14 × 1,239.86
4. Step 4: Simplify right side
   2,287.80x = 3,914,411.60
5. Step 5: Solve for x
   x = 3,914,411.60/2,287.80
6. Step 6: Final answer
   x = 1,710.99