Finding the Fourth Proportional to 21,861.34, 30,167.39 and 12,905.58

Step by Step Solution

1. Step 1: Write the proportion equation
   21,861.34 : 30,167.39 = 12,905.58 : x
2. Step 2: Convert to fraction form
   21,861.34/30,167.39 = 12,905.58/x
3. Step 3: Cross multiply
   21,861.34x = 30,167.39 × 12,905.58
4. Step 4: Simplify right side
   21,861.34x = 389,327,568.14
5. Step 5: Solve for x
   x = 389,327,568.14/21,861.34
6. Step 6: Final answer
   x = 17,808.95