Finding the Fourth Proportional to 13,665.78, 18,858.98 and 7,615.85

Step by Step Solution

1. Step 1: Write the proportion equation
   13,665.78 : 18,858.98 = 7,615.85 : x
2. Step 2: Convert to fraction form
   13,665.78/18,858.98 = 7,615.85/x
3. Step 3: Cross multiply
   13,665.78x = 18,858.98 × 7,615.85
4. Step 4: Simplify right side
   13,665.78x = 143,627,171.90
5. Step 5: Solve for x
   x = 143,627,171.90/13,665.78
6. Step 6: Final answer
   x = 10,509.99