Finding the Fourth Proportional to 13,405.39, 18,500.43 and 7,438.21

Step by Step Solution

1. Step 1: Write the proportion equation
   13,405.39 : 18,500.43 = 7,438.21 : x
2. Step 2: Convert to fraction form
   13,405.39/18,500.43 = 7,438.21/x
3. Step 3: Cross multiply
   13,405.39x = 18,500.43 × 7,438.21
4. Step 4: Simplify right side
   13,405.39x = 137,610,083.43
5. Step 5: Solve for x
   x = 137,610,083.43/13,405.39
6. Step 6: Final answer
   x = 10,265.28