# Circle | Part-2 | S N Dey

In the previous article , we discussed 10 Very Short Answer Type Questions. In this article, we will discuss few more VSA type Questions from Chhaya Mathematics , Class 11 (S N De book ).

##### Circle related Problems and Solutions | S N Dey Mathematics

11. The co-ordinates of the centre of the circle are ; find and

Solution.

The given equation of the circle can be rewritten as :

Now, comparing the equation with the general / standard form of circle we get,

So, the centre of the circle as represented by is :

By we get,

12. Find the equation of the circle which touches both the co-ordinate axes at a distance unit from the origin.

Solution.

From the given condition, we can say that the centre of the circle is and the radius of the circle is unit so that the equation of the circle can be written as :

13. Find the parametric equation of the circle

Solution.

We have,

Comparing the equation with the general / standard form of circle we get,

The centre of the given circle is :

The radius of the circle :

Hence, the equation of the circle is :

By we get,

The equations together represent the parametric equation of the circle.

14. The parametric equation of a circle are, Find the equation of the circle.

Solution.

We have,

Hence, from we get,

15. The equation of the in-circle of an equilateral triangle is find the area of the equilateral triangle.

Solution.

The equation of the in-circle of an equilateral triangle is given by

Comparing the equation with the general / standard form of circle we get,

The radius of the circle is :

Clearly, from the figure we notice that Now let so that