Use a graphing tool and you'll see a circle form. This circle has a center of (0,0) and radius of 4. Side note: this equation is equivalent to x^2+y^2 = 16 after you divide everything by 4
Looking at the graph, the smallest x can be is -4. The largest x can be is 4. So the domain in interval notation is
![[-4,4]](https://tex.z-dn.net/?f=%5B-4%2C4%5D)
Similarly the range in interval notation is also <span>
![[-4,4]](https://tex.z-dn.net/?f=%5B-4%2C4%5D)
because the lowest you can go is y = -4. The highest you can go is y = 4</span>
You take 12 * 6 = 72, then divide by two. 72 / 2 = 36 in squared