Finding the Third Proportional to 8,064 and 12,640

Step by Step Solution

1. Step 1: Write the proportion equation
   8,064 : 12,640 = 12,640 : x
2. Step 2: Convert to fraction form
   8,064/12,640 = 12,640/x
3. Step 3: Cross multiply
   8,064x = 12,640 × 12,640
4. Step 4: Simplify right side
   8,064x = 159,769,600
5. Step 5: Solve for x
   x = 159,769,600/8,064
6. Step 6: Final answer
   x = 19,812.70