Finding the Fourth Proportional to 21,834.76, 30,128.34 and 12,399.88

Step by Step Solution

1. Step 1: Write the proportion equation
   21,834.76 : 30,128.34 = 12,399.88 : x
2. Step 2: Convert to fraction form
   21,834.76/30,128.34 = 12,399.88/x
3. Step 3: Cross multiply
   21,834.76x = 30,128.34 × 12,399.88
4. Step 4: Simplify right side
   21,834.76x = 373,587,800.60
5. Step 5: Solve for x
   x = 373,587,800.60/21,834.76
6. Step 6: Final answer
   x = 17,109.77