More practice with equations of circles

Today started with going through the responses of the homework problems. The only issue appeared on the problem where 3 tangent lines defined the boundary of the circle. I drew out the representation and asked the class what they knew about the center of the circle in relation to the lines x = 8 and
x = 14? The class understood the center would lay half way between these two lines. From this, I asked what the radius had to be? Students saw that the radius was 3 units. Given the tangent line y = 3, students realized the circle center had to be above this line.

We then worked on problems from the Great Minds unit lesson on circles. The first set of problems went quickly. Students appeared to be comfortable with writing equations or giving the center and radius when given an equation. Few students were making the common mistakes that I saw last class.

We'll continue practicing with circle equations on Friday and start to move toward reversing the process, i.e. re-writing expressions to standard equation form.