Finding the Fourth Proportional to 21,839.76, 30,136.86 and 12,406.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,839.76 : 30,136.86 = 12,406.50 : x
2. Step 2: Convert to fraction form
   21,839.76/30,136.86 = 12,406.50/x
3. Step 3: Cross multiply
   21,839.76x = 30,136.86 × 12,406.50
4. Step 4: Simplify right side
   21,839.76x = 373,892,953.59
5. Step 5: Solve for x
   x = 373,892,953.59/21,839.76
6. Step 6: Final answer
   x = 17,119.83