Finding the Fourth Proportional to 3,909.78, 5,868.80 and 3,821.63

Step by Step Solution

1. Step 1: Write the proportion equation
   3,909.78 : 5,868.80 = 3,821.63 : x
2. Step 2: Convert to fraction form
   3,909.78/5,868.80 = 3,821.63/x
3. Step 3: Cross multiply
   3,909.78x = 5,868.80 × 3,821.63
4. Step 4: Simplify right side
   3,909.78x = 22,428,333.69
5. Step 5: Solve for x
   x = 22,428,333.69/3,909.78
6. Step 6: Final answer
   x = 5,736.47