Finding the Fourth Proportional to 8,491.63, 12,720.88 and 5,561.05

Step by Step Solution

1. Step 1: Write the proportion equation
   8,491.63 : 12,720.88 = 5,561.05 : x
2. Step 2: Convert to fraction form
   8,491.63/12,720.88 = 5,561.05/x
3. Step 3: Cross multiply
   8,491.63x = 12,720.88 × 5,561.05
4. Step 4: Simplify right side
   8,491.63x = 70,741,449.72
5. Step 5: Solve for x
   x = 70,741,449.72/8,491.63
6. Step 6: Final answer
   x = 8,330.73