Finding the Fourth Proportional to 12,086.16, 18,128.60 and 3,320.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,086.16 : 18,128.60 = 3,320.40 : x
2. Step 2: Convert to fraction form
   12,086.16/18,128.60 = 3,320.40/x
3. Step 3: Cross multiply
   12,086.16x = 18,128.60 × 3,320.40
4. Step 4: Simplify right side
   12,086.16x = 60,194,203.44
5. Step 5: Solve for x
   x = 60,194,203.44/12,086.16
6. Step 6: Final answer
   x = 4,980.42