Finding the Fourth Proportional to 2,665.98, 3,997.50 and 1,239.66

Step by Step Solution

1. Step 1: Write the proportion equation
   2,665.98 : 3,997.50 = 1,239.66 : x
2. Step 2: Convert to fraction form
   2,665.98/3,997.50 = 1,239.66/x
3. Step 3: Cross multiply
   2,665.98x = 3,997.50 × 1,239.66
4. Step 4: Simplify right side
   2,665.98x = 4,955,540.85
5. Step 5: Solve for x
   x = 4,955,540.85/2,665.98
6. Step 6: Final answer
   x = 1,858.81