Circles class 10 notes i.e. for chapter 10 provided here are an extremely important resource for the students studying in CBSE class 10. Students can use these notes to quickly understand the topics covered in this chapter and revise the concepts quickly. In this chapter 10 notes, the following topics are covered-

- Definition of a circle
- What is a tangent
- Theorems related to tangents

## What is a Circle?

A circle is defined as a closed shape with a set of points in a plane which are at a specific distance from the center. This specific distance is known to be the radius of a circle. It is important to learn all the details about a circle along with some important points associated with it like locus, circumference, area, etc. which are explained in the linked article.

## Tangent to a Circle

A tangent is defined as a line that intersects the circle at only one point. For any point on the circumference of a circle, there exists one and only one tangent at that point of a circle.

### Theorems Related to Tangent of a Circle

There are two theorems related to the tangent of a circle which are:

**Theorem 1: **The tangent at any point of a circle is perpendicular to the radius through the point of contact. The prove of this theorem is also given below.

**Theorem 2: **The lengths of tangents drawn from an external point to a circle are equal. Below given is the proof of theorem 2.

### Example Question

### Sample Questions from Circle

- The tangents drawn at the ends of a diameter of a circle are parallel. Prove.
- Find the radius of a circle if the length of a tangent from a point X at a distance 5 cm from the centre of the circle is 4 cm.
- Prove that a parallelogram circumscribing a circle is always a rhombus.

### Related Concepts

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