Finding the Fourth Proportional to 8,320, 12,478.72 and 3,389.52

Step by Step Solution

1. Step 1: Write the proportion equation
   8,320 : 12,478.72 = 3,389.52 : x
2. Step 2: Convert to fraction form
   8,320/12,478.72 = 3,389.52/x
3. Step 3: Cross multiply
   8,320x = 12,478.72 × 3,389.52
4. Step 4: Simplify right side
   8,320x = 42,296,871.01
5. Step 5: Solve for x
   x = 42,296,871.01/8,320
6. Step 6: Final answer
   x = 5,083.76