Finding the Fourth Proportional to 7,864.80, 10,856.75 and 5,216.10

Step by Step Solution

1. Step 1: Write the proportion equation
   7,864.80 : 10,856.75 = 5,216.10 : x
2. Step 2: Convert to fraction form
   7,864.80/10,856.75 = 5,216.10/x
3. Step 3: Cross multiply
   7,864.80x = 10,856.75 × 5,216.10
4. Step 4: Simplify right side
   7,864.80x = 56,629,867.59
5. Step 5: Solve for x
   x = 56,629,867.59/7,864.80
6. Step 6: Final answer
   x = 7,200.42