Finding the Fourth Proportional to 8,617.76, 12,909.72 and 5,687.12

Step by Step Solution

1. Step 1: Write the proportion equation
   8,617.76 : 12,909.72 = 5,687.12 : x
2. Step 2: Convert to fraction form
   8,617.76/12,909.72 = 5,687.12/x
3. Step 3: Cross multiply
   8,617.76x = 12,909.72 × 5,687.12
4. Step 4: Simplify right side
   8,617.76x = 73,419,126.81
5. Step 5: Solve for x
   x = 73,419,126.81/8,617.76
6. Step 6: Final answer
   x = 8,519.51