Finding the Fourth Proportional to 13,438.72, 20,162.13 and 5,429.37

Step by Step Solution

1. Step 1: Write the proportion equation
   13,438.72 : 20,162.13 = 5,429.37 : x
2. Step 2: Convert to fraction form
   13,438.72/20,162.13 = 5,429.37/x
3. Step 3: Cross multiply
   13,438.72x = 20,162.13 × 5,429.37
4. Step 4: Simplify right side
   13,438.72x = 109,467,663.76
5. Step 5: Solve for x
   x = 109,467,663.76/13,438.72
6. Step 6: Final answer
   x = 8,145.69