Finding the Fourth Proportional to 13,388.56, 18,476.89 and 7,420.25

Step by Step Solution

1. Step 1: Write the proportion equation
   13,388.56 : 18,476.89 = 7,420.25 : x
2. Step 2: Convert to fraction form
   13,388.56/18,476.89 = 7,420.25/x
3. Step 3: Cross multiply
   13,388.56x = 18,476.89 × 7,420.25
4. Step 4: Simplify right side
   13,388.56x = 137,103,170.66
5. Step 5: Solve for x
   x = 137,103,170.66/13,388.56
6. Step 6: Final answer
   x = 10,240.32