Finding the Fourth Proportional to 6,102.20, 8,421.72 and 5,105.72

Step by Step Solution

1. Step 1: Write the proportion equation
   6,102.20 : 8,421.72 = 5,105.72 : x
2. Step 2: Convert to fraction form
   6,102.20/8,421.72 = 5,105.72/x
3. Step 3: Cross multiply
   6,102.20x = 8,421.72 × 5,105.72
4. Step 4: Simplify right side
   6,102.20x = 42,998,944.24
5. Step 5: Solve for x
   x = 42,998,944.24/6,102.20
6. Step 6: Final answer
   x = 7,046.47