# How do you write the equation of a circle with center(3,-4)and radius of 7?

##### 1 Answer

#### Answer:

#### Explanation:

The unit circle, centered in the origin, has equation

This means that the squared lenght of the vector

Now we want to move the center as well, let's say that our new center is

With respect to these new coordinates, the circle is again centered in the origin, so it has equation

Plug back the definition, and you have the final result

Plugging your particular values, the equation is

If you like, you can do some manipulations: