Finding the Fourth Proportional to 2,287.58, 3,156.86 and 1,239.63

Step by Step Solution

1. Step 1: Write the proportion equation
   2,287.58 : 3,156.86 = 1,239.63 : x
2. Step 2: Convert to fraction form
   2,287.58/3,156.86 = 1,239.63/x
3. Step 3: Cross multiply
   2,287.58x = 3,156.86 × 1,239.63
4. Step 4: Simplify right side
   2,287.58x = 3,913,332.16
5. Step 5: Solve for x
   x = 3,913,332.16/2,287.58
6. Step 6: Final answer
   x = 1,710.69