Finding the Fourth Proportional to 13,276.50, 18,321.57 and 7,687.50

Step by Step Solution

1. Step 1: Write the proportion equation
   13,276.50 : 18,321.57 = 7,687.50 : x
2. Step 2: Convert to fraction form
   13,276.50/18,321.57 = 7,687.50/x
3. Step 3: Cross multiply
   13,276.50x = 18,321.57 × 7,687.50
4. Step 4: Simplify right side
   13,276.50x = 140,847,069.38
5. Step 5: Solve for x
   x = 140,847,069.38/13,276.50
6. Step 6: Final answer
   x = 10,608.75