Finding the Fourth Proportional to 13,396.58, 18,487.71 and 7,428.80

Step by Step Solution

1. Step 1: Write the proportion equation
   13,396.58 : 18,487.71 = 7,428.80 : x
2. Step 2: Convert to fraction form
   13,396.58/18,487.71 = 7,428.80/x
3. Step 3: Cross multiply
   13,396.58x = 18,487.71 × 7,428.80
4. Step 4: Simplify right side
   13,396.58x = 137,341,500.05
5. Step 5: Solve for x
   x = 137,341,500.05/13,396.58
6. Step 6: Final answer
   x = 10,251.98