Finding the Fourth Proportional to 21,144.59, 31,719.87 and 8,666.42

Step by Step Solution

1. Step 1: Write the proportion equation
   21,144.59 : 31,719.87 = 8,666.42 : x
2. Step 2: Convert to fraction form
   21,144.59/31,719.87 = 8,666.42/x
3. Step 3: Cross multiply
   21,144.59x = 31,719.87 × 8,666.42
4. Step 4: Simplify right side
   21,144.59x = 274,897,715.77
5. Step 5: Solve for x
   x = 274,897,715.77/21,144.59
6. Step 6: Final answer
   x = 13,000.85