Students will understand that:

• A tangent to a circle intersects the circle in only one point and is perpendicular to the radius of the circle at that point.
• A line through the centre of a circle that is perpendicular to a chord bisects the chord.
• Inscribed angles subtended by the same arc are congruent and their measures are one-half the measure of the central angle subtended by the same arc.
• Geometric properties of angles and chords in a circle and tangents to a circle can be used to determine angle and line segment measures.

Essential Questions:

• What is a radius? What is a tangent? What is a point of Tangency?
• What does perpendicular mean? What is a chord? What is a perpendicular bisector?

General Outcomes:

• Students will use direct or indirect measurement to solve problems.
  • Students will solve problems and justify the solution strategy using circle properties
    • The perpendicular from the centre of a circle to a chord bisects the chord.
    • The measure of the central angle is equal to twice the measure of the inscribed angle subtended by the same arc.
    • The inscribed angles subtended by the arc are equal.
    • A tangent to a circle is perpendicular to the radius at the point of tangency.