Finding the Fourth Proportional to 2,643.76, 3,963.40 and 1,325.89

Step by Step Solution

1. Step 1: Write the proportion equation
   2,643.76 : 3,963.40 = 1,325.89 : x
2. Step 2: Convert to fraction form
   2,643.76/3,963.40 = 1,325.89/x
3. Step 3: Cross multiply
   2,643.76x = 3,963.40 × 1,325.89
4. Step 4: Simplify right side
   2,643.76x = 5,255,012.61
5. Step 5: Solve for x
   x = 5,255,012.61/2,643.76
6. Step 6: Final answer
   x = 1,987.71