Finding the Fourth Proportional to 13,692.78, 18,895.98 and 7,405.20

Step by Step Solution

1. Step 1: Write the proportion equation
   13,692.78 : 18,895.98 = 7,405.20 : x
2. Step 2: Convert to fraction form
   13,692.78/18,895.98 = 7,405.20/x
3. Step 3: Cross multiply
   13,692.78x = 18,895.98 × 7,405.20
4. Step 4: Simplify right side
   13,692.78x = 139,928,511.10
5. Step 5: Solve for x
   x = 139,928,511.10/13,692.78
6. Step 6: Final answer
   x = 10,219.15