Finding the Fourth Proportional to 20,900.55, 31,350.42 and 5,105.69

Step by Step Solution

1. Step 1: Write the proportion equation
   20,900.55 : 31,350.42 = 5,105.69 : x
2. Step 2: Convert to fraction form
   20,900.55/31,350.42 = 5,105.69/x
3. Step 3: Cross multiply
   20,900.55x = 31,350.42 × 5,105.69
4. Step 4: Simplify right side
   20,900.55x = 160,065,525.89
5. Step 5: Solve for x
   x = 160,065,525.89/20,900.55
6. Step 6: Final answer
   x = 7,658.44