Finding the Fourth Proportional to 3,921.72, 5,423.99 and 3,856.11

Step by Step Solution

1. Step 1: Write the proportion equation
   3,921.72 : 5,423.99 = 3,856.11 : x
2. Step 2: Convert to fraction form
   3,921.72/5,423.99 = 3,856.11/x
3. Step 3: Cross multiply
   3,921.72x = 5,423.99 × 3,856.11
4. Step 4: Simplify right side
   3,921.72x = 20,915,482.80
5. Step 5: Solve for x
   x = 20,915,482.80/3,921.72
6. Step 6: Final answer
   x = 5,333.24