Finding the Fourth Proportional to 12,064.80, 18,072.90 and 8,128.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,064.80 : 18,072.90 = 8,128.20 : x
2. Step 2: Convert to fraction form
   12,064.80/18,072.90 = 8,128.20/x
3. Step 3: Cross multiply
   12,064.80x = 18,072.90 × 8,128.20
4. Step 4: Simplify right side
   12,064.80x = 146,900,145.78
5. Step 5: Solve for x
   x = 146,900,145.78/12,064.80
6. Step 6: Final answer
   x = 12,175.93