Finding the Fourth Proportional to 10,687.86, 16,010.02 and 8,720.50

Step by Step Solution

1. Step 1: Write the proportion equation
   10,687.86 : 16,010.02 = 8,720.50 : x
2. Step 2: Convert to fraction form
   10,687.86/16,010.02 = 8,720.50/x
3. Step 3: Cross multiply
   10,687.86x = 16,010.02 × 8,720.50
4. Step 4: Simplify right side
   10,687.86x = 139,615,379.41
5. Step 5: Solve for x
   x = 139,615,379.41/10,687.86
6. Step 6: Final answer
   x = 13,062.99