Finding the Fourth Proportional to 2,603.97, 3,900.72 and 1,215.39

Step by Step Solution

1. Step 1: Write the proportion equation
   2,603.97 : 3,900.72 = 1,215.39 : x
2. Step 2: Convert to fraction form
   2,603.97/3,900.72 = 1,215.39/x
3. Step 3: Cross multiply
   2,603.97x = 3,900.72 × 1,215.39
4. Step 4: Simplify right side
   2,603.97x = 4,740,896.08
5. Step 5: Solve for x
   x = 4,740,896.08/2,603.97
6. Step 6: Final answer
   x = 1,820.64