Finding the Fourth Proportional to 9,320, 12,861.60 and 5,128.16

Step by Step Solution

1. Step 1: Write the proportion equation
   9,320 : 12,861.60 = 5,128.16 : x
2. Step 2: Convert to fraction form
   9,320/12,861.60 = 5,128.16/x
3. Step 3: Cross multiply
   9,320x = 12,861.60 × 5,128.16
4. Step 4: Simplify right side
   9,320x = 65,956,342.66
5. Step 5: Solve for x
   x = 65,956,342.66/9,320
6. Step 6: Final answer
   x = 7,076.86