Finding the Fourth Proportional to 13,429.68, 20,139.33 and 5,105.31

Step by Step Solution

1. Step 1: Write the proportion equation
   13,429.68 : 20,139.33 = 5,105.31 : x
2. Step 2: Convert to fraction form
   13,429.68/20,139.33 = 5,105.31/x
3. Step 3: Cross multiply
   13,429.68x = 20,139.33 × 5,105.31
4. Step 4: Simplify right side
   13,429.68x = 102,817,522.84
5. Step 5: Solve for x
   x = 102,817,522.84/13,429.68
6. Step 6: Final answer
   x = 7,655.99