Finding the Fourth Proportional to 12,171.12, 18,279.72 and 8,715.12

Step by Step Solution

1. Step 1: Write the proportion equation
   12,171.12 : 18,279.72 = 8,715.12 : x
2. Step 2: Convert to fraction form
   12,171.12/18,279.72 = 8,715.12/x
3. Step 3: Cross multiply
   12,171.12x = 18,279.72 × 8,715.12
4. Step 4: Simplify right side
   12,171.12x = 159,309,953.37
5. Step 5: Solve for x
   x = 159,309,953.37/12,171.12
6. Step 6: Final answer
   x = 13,089.18