## What is the radius of a tangent circle?

The radius of a circle is perpendicular to the tangent line through its endpoint on the circle’s circumference. Conversely, the perpendicular to a radius through the same endpoint is a tangent line. The resulting geometrical figure of circle and tangent line has a reflection symmetry about the axis of the radius.

## What is the relationship between a circle and a tangent to the circle?

A tangent to a circle is a straight line which touches the circle at only one point. This point is called the point of tangency. The tangent to a circle is perpendicular to the radius at the point of tangency. In the circle O , ↔PT is a tangent and ¯OP is the radius.

**What is a common tangent of a circle?**

Definition of Common Tangent A tangent to a circle is a line that passes through exactly one point on a circle and is perpendicular to a line passing through the center of the circle. Internal common tangents, which pass through the line segment joining the centers of the two circles.

### How do you find the common tangent between two circles?

For finding direct common tangents of two circles, find the point P dividing the line joining the centre externally in the ratio of the radii. Equation of direct common tangents is SS1 = T2 where S is the equation of one circle.

### What does it mean when a segment is tangent to a circle?

A tangent line is a line that intersects a circle at one point. A tangent segment is a segment with one endpoint at the point of tangency and its other endpoint somewhere on the tangent line. A tangent segment is also perpendicular to the radius of the circle whose endpoint is the point of tangency.

**What is the common tangent procedure?**

From the center of the smaller circle, draw a segment parallel to the common tangent till it hits the radius of the larger circle (or the extension of the radius in a common-internal-tangent problem). You end up with a right triangle and a rectangle; one of the rectangle’s sides is the common tangent.

## What is no common tangent?

1. No Common Tangent: If one circle line completely inside another circle without cutting or touching it at any point then the circles will have no common tangent. Three Common Tangents: If two circles touch each other externally at one point, they will have three common tangents.

## What is the formula of common tangent?

Use the formula $c=\dfrac{a}{m}$ to get one equation. Then use the fact that for the line y = mx + c to become tangent to the circle, the perpendicular distance from the centre of the circle to the line should be equal to radius of the circle to find another equation.

**How to construct direct commom tangents to circles of different radii?**

PQ and RS are the required TANGENTS to circles C1 and C2 Step 2: Draw two circles ‘C1’ and ‘C2’ with radius R = r = 6 cm and center as ‘A’ and ‘B’ respectively. Step 6: Join PQ and RS.

### Can a circle have an external or internal tangent?

If they intersect at one point then they can either be externally tangent or internally tangent. Two circles that do not intersect can either have a common external tangent or common internal tangent. In the common external tangent, the tangent does not cross between the two circles.

### How are circles of radii 36 and 9 related?

Circles of radii 36 and 9 touch externally. The radius of the circle which touches the two circles externally and also their common tangent is : Circles of radii 36 and 9 touch externally. The radius of the circle which touches the two circles externally and also their common tangent is :

**When is a tangent perpendicular to the radius?**

A tangent is perpendicular to the radius at the point of contact. The point of tangency is where a tangent line touches the circle. In the above diagram, the line containing the points B and C is a tangent to the circle. It touches the circle at point B and is perpendicular to the radius . Point B is called the point of tangency.