Exercise 48 Page 786

Let's start by recalling the standard form of an equation of a circle. (x- h)^2+(y- k)^2= r^2 In this form, ( h, k) is the center of the circle and r is its radius. We are told that the center of the circle is ( - 3, - 10) and its diameter is 24. The radius of a circle is half the length of the diameter so the radius of this circle is 12. This information is enough to write the equation. (x-( - 3))^2+(y-( - 10))^2= 12^2 ⇕ (x+3)^2+(y+10)^2=144