Finding the Fourth Proportional to 3,938.78, 5,424.96 and 3,643.16

Step by Step Solution

1. Step 1: Write the proportion equation
   3,938.78 : 5,424.96 = 3,643.16 : x
2. Step 2: Convert to fraction form
   3,938.78/5,424.96 = 3,643.16/x
3. Step 3: Cross multiply
   3,938.78x = 5,424.96 × 3,643.16
4. Step 4: Simplify right side
   3,938.78x = 19,763,997.27
5. Step 5: Solve for x
   x = 19,763,997.27/3,938.78
6. Step 6: Final answer
   x = 5,017.80