Finding the Fourth Proportional to 13,605.76, 18,774.50 and 7,638.08

Step by Step Solution

1. Step 1: Write the proportion equation
   13,605.76 : 18,774.50 = 7,638.08 : x
2. Step 2: Convert to fraction form
   13,605.76/18,774.50 = 7,638.08/x
3. Step 3: Cross multiply
   13,605.76x = 18,774.50 × 7,638.08
4. Step 4: Simplify right side
   13,605.76x = 143,401,141.71
5. Step 5: Solve for x
   x = 143,401,141.71/13,605.76
6. Step 6: Final answer
   x = 10,539.74