Finding the Fourth Proportional to 12,156.62, 18,215.48 and 10,990.22

Step by Step Solution

1. Step 1: Write the proportion equation
   12,156.62 : 18,215.48 = 10,990.22 : x
2. Step 2: Convert to fraction form
   12,156.62/18,215.48 = 10,990.22/x
3. Step 3: Cross multiply
   12,156.62x = 18,215.48 × 10,990.22
4. Step 4: Simplify right side
   12,156.62x = 200,192,132.61
5. Step 5: Solve for x
   x = 200,192,132.61/12,156.62
6. Step 6: Final answer
   x = 16,467.75