Finding the Fourth Proportional to 13,389.69, 18,477.27 and 7,421.21

Step by Step Solution

1. Step 1: Write the proportion equation
   13,389.69 : 18,477.27 = 7,421.21 : x
2. Step 2: Convert to fraction form
   13,389.69/18,477.27 = 7,421.21/x
3. Step 3: Cross multiply
   13,389.69x = 18,477.27 × 7,421.21
4. Step 4: Simplify right side
   13,389.69x = 137,123,608.51
5. Step 5: Solve for x
   x = 137,123,608.51/13,389.69
6. Step 6: Final answer
   x = 10,240.98