Finding the Fourth Proportional to 16,920.72, 23,340.42 and 12,456

Step by Step Solution

1. Step 1: Write the proportion equation
   16,920.72 : 23,340.42 = 12,456 : x
2. Step 2: Convert to fraction form
   16,920.72/23,340.42 = 12,456/x
3. Step 3: Cross multiply
   16,920.72x = 23,340.42 × 12,456
4. Step 4: Simplify right side
   16,920.72x = 290,728,271.52
5. Step 5: Solve for x
   x = 290,728,271.52/16,920.72
6. Step 6: Final answer
   x = 17,181.79