Finding the Fourth Proportional to 13,838.91, 20,757.68 and 3,978.10

Step by Step Solution

1. Step 1: Write the proportion equation
   13,838.91 : 20,757.68 = 3,978.10 : x
2. Step 2: Convert to fraction form
   13,838.91/20,757.68 = 3,978.10/x
3. Step 3: Cross multiply
   13,838.91x = 20,757.68 × 3,978.10
4. Step 4: Simplify right side
   13,838.91x = 82,576,126.81
5. Step 5: Solve for x
   x = 82,576,126.81/13,838.91
6. Step 6: Final answer
   x = 5,966.95