Finding the Fourth Proportional to 8,561.13, 12,820.72 and 7,071.23

Step by Step Solution

1. Step 1: Write the proportion equation
   8,561.13 : 12,820.72 = 7,071.23 : x
2. Step 2: Convert to fraction form
   8,561.13/12,820.72 = 7,071.23/x
3. Step 3: Cross multiply
   8,561.13x = 12,820.72 × 7,071.23
4. Step 4: Simplify right side
   8,561.13x = 90,658,259.89
5. Step 5: Solve for x
   x = 90,658,259.89/8,561.13
6. Step 6: Final answer
   x = 10,589.52