Fill in the blank with a number to make the expression a perfect square.
![Fill in the blank with a number to make the expression a perfect square class=](https://us-static.z-dn.net/files/d31/b1e3aecc42af91804fb0d103044e2e40.png)
Answer: 16
Step-by-step explanation:
It divides evenly into (w-4)^2.