# Given the centre (0,0) and a tangent that has the equation 3x-4y=30, what is the equation of the circle?

##### 2 Answers

#### Explanation:

Length of a perpendicular from a point

Hence length of perpendicular from

But this is radius of the circle. Hence, equation of circle will be

Reqd. eqn. of the circle is

#### Explanation:

To determine the eqn. of a circle, we need its (i) centre, and, (ii) the

radius. As the centre is given to be the Origin

suppose that the radius of the circle is

Now the line

**Geometry** , we know that the **

Centre ** to the **tgt. line** #l# must equal **radius

Now, the eqn. of a circle having centre at

given by,

eqn. is

Note : The

is