# CBSE Class 10-Mathematics: Questions and Answers Chapter –10 Circles Part 9

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**Question 19:**

If AB, AC and PQ are tangents in the given figure and , find the perimeter of .

**Answer:**

Perimeter of

**Question 20:**

Find the locus of the center of circles which touch a given line at a given point.

**Answer:**

Let APB be the given line and let a circle with center O touch APB at P. Then , let there be another circle with center O’ which touches the line APB at P.

Thus,

**Question 21:**

In the given figure, find the perimeter of if .

**Answer:**

BC touches the circle at R

Tangents drawn from external point to the circle are equal.

And

Perimeter of

**Question 22:**

If PA and PB are tangents drawn from external point P such that and

**Answer:**

[O is centre of circle]

is equilateral triangle

**Question 23:**

If AB, AC and PQ are tangents in the given figure and , find the perimeter of .

**Answer:**

Perimeter of