# What are the six circle theorems?

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In geometry, the six circles theorem relates to a chain of six circles together with a triangle, such that each circle is tangent to two sides of the triangle and also to the preceding circle in the chain. The chain closes, in the sense that the sixth circle is always tangent to the first circle.

Herein, what are the 7 circle theorems?

• Circle Theorem 1 - Angle at the Centre.
• Circle Theorem 2 - Angles in a Semicircle.
• Circle Theorem 3 - Angles in the Same Segment.
• Circle Theorem 4 - Cyclic Quadrilateral.
• Circle Theorem 5 - Radius to a Tangent.
• Circle Theorem 6 - Tangents from a Point to a Circle.
• Circle Theorem 7 - Tangents from a Point to a Circle II.

Secondly, what are the 9 circle theorems? First circle theorem - angles at the centre and at the circumference. Second circle theorem - angle in a semicircle. Third circle theorem - angles in the same segment. Fourth circle theorem - angles in a cyclic quadlateral.

Regarding this, how many circle theorems are there?

8 circle theorems

What are the circle theorems rules?

• The angle at the centre is twice the angle at the circumference.
• The angle in a semicircle is a right angle.
• Angles in the same segment are equal.
• Opposite angles in a cyclic quadrilateral sum to 180°
• The angle between the chord and the tangent is equal to the angle in the alternate segment.

360

### What is a math theorem?

A theorem is a statement that can be demonstrated to be true by accepted mathematical operations and arguments. In general, a theorem is an embodiment of some general principle that makes it part of a larger theory. The process of showing a theorem to be correct is called a proof.

### What is a reflex angle?

Reflex angles are angles measuring greater than 180 degrees and less than 360 degrees. The measure of a reflex angle is added to an acute or obtuse angle to make a full 360 degree circle.

### Are of a circle?

The area of a circle is pi times the radius squared (A = π r²). Learn how to use this formula to find the area of a circle when given the diameter.

### What is a triangle in a circle?

The triangle within a circle is an ancient occult symbol dating back to the ancient civilizations. The equilateral triangle represents the three part answer - unity, recovery and service - to a three part disease - physical, mental and spiritual, while the circle represents wholeness or oneness.

### Are all triangles cyclic?

All (nondegenerate) triangles and all regular polygons are cyclic. When talking about a cyclic polygon, the circle in which it can be inscribed is called its circumcircle. The radius of this circle is known as the circumradius of the polygon.

### Is a circle an angle?

A circle is the same as 360°. You can divide a circle into smaller portions. A part of a circle is called an arc and an arc is named according to its angle. When diameters intersect at the central of the circle they form central angles.

### How do you find the length of a chord?

The formula for the chord length is: 2rsin(theta/2) where r is the radius of the circle and theta is the angle from the centre of the circle to the two points of the chord.

### What are the properties of a circle?

The three most important properties to remember are the circumference, which is the distance around the shape; the diameter, which is the distance from one end of the circle to the other crossing through the center; and the radius, which is half of the diameter.

### What is a circle in maths?

(Math | Geometry | Circles)
a circle. Definition: A circle is the locus of all points equidistant from a central point. Definitions Related to Circles. arc: a curved line that is part of the circumference of a circle. chord: a line segment within a circle that touches 2 points on the circle.

360 degrees

### How do I find the length of an arc?

To find arc length, start by dividing the arc's central angle in degrees by 360. Then, multiply that number by the radius of the circle. Finally, multiply that number by 2 × pi to find the arc length.

### Who invented circle theorems?

The greeks considered the Egyptians as the inventors of geometry. The scribe Ahmes, the author of the Rhind papyrus, gives a rule for determining the area of a circle which corresponds to π = 256/81 or approximately 3.16. The first theorems relating to circles are attributed to Thales around 650 BC.

### What is a segment of a circle?

Segments of a Circle. A chord of a circle divides the circle into two regions, which are called the segments of the circle. The minor segment is the region bounded by the chord and the minor arc intercepted by the chord. The major segment is the region bounded by the chord and the major arc intercepted by the chord.

### How do you find the center and radius of a circle?

The center-radius form of the circle equation is in the format (x – h)2 + (y – k)2 = r2, with the center being at the point (h, k) and the radius being "r". This form of the equation is helpful, since you can easily find the center and the radius.

### What is circle theory?

The definition of a circle is: A set of points in a plane that are equidistant to a given point, the centre. The blue line in the drawing below is the circle. The distance between the centre and the circle is called the radius*1. The distance circle-circle through the centre is called the diameter.