## Geometry

### Circles

Circles and lines have important connections. The lessons in this unit examine secant lines and tangent lines and their relationships to each other and to a circle. Students explore the measures of the arcs and angles formed when lines intersect a circle and the relationships between intersecting secant lines and segments formed by these lines. They also work with circles in the coordinate plane.

### Geometry: Circles Activities

Title Type

#### Tangents to a Circle

Explore properties of tangent lines and how they differ from secant lines.

• 6763

#### Circles - Angles and Arcs

Investigate inscribed angles, central angles and intercepted arcs relationships in circles.

• 7158

#### Chords of a Circle

Explore the relationship between chords of a circle and their perpendicular bisectors.

• 6628

#### Secants, Tangents and Arcs

Explore the angle and arc relationships for two intersecting lines that intersect a circle.

• 6912

#### Positive and Negative Angles and Arcs

Investigate the relationships among the angles of intersection of the two lines and the intercepted arcs using positive and negative angle and arc measures.

• 4377

#### Intersecting Lines and Segment Measures

Explore the relationship between intersecting lines and the measures of various segments on those lines.

• 6395

Explore the relationship between chords of a circle and their perpendicular bisectors.

• 6313

#### Exploring the Equation of a Circle

Explore right triangles and the Pythagorean Theorem to develop the equation of a circle.

• 6663