Finding the Third Proportional to 8,616 and 12,890

Step by Step Solution

1. Step 1: Write the proportion equation
   8,616 : 12,890 = 12,890 : x
2. Step 2: Convert to fraction form
   8,616/12,890 = 12,890/x
3. Step 3: Cross multiply
   8,616x = 12,890 × 12,890
4. Step 4: Simplify right side
   8,616x = 166,152,100
5. Step 5: Solve for x
   x = 166,152,100/8,616
6. Step 6: Final answer
   x = 19,284.13