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Flashcards · Maths · Circle Theorems

Tangents and Chords

16 cards

  1. What is a tangent?

    A straight line that touches a circle at one point.

  2. What is a chord?

    A straight line joining two points on a circle.

  3. What is the angle between a tangent and the radius at the point of contact?

    \(90^\circ\).

  4. What is true of tangents from the same point to a circle?

    They are equal in length.

  5. What shape do two tangents and the two radii to the points of contact make?

    A kite.

  6. What do the angles of a quadrilateral add up to?

    \(360^\circ\).

  7. What does a perpendicular from the centre do to a chord?

    It bisects it.

  8. What is the reason for a right angle at a point of contact?

    A tangent is perpendicular to the radius.

  9. What is the shortest distance from the centre to a chord?

    The perpendicular distance.

  10. What triangle is formed by the centre and the ends of a chord?

    An isosceles triangle, because two sides are radii.

  11. What do you use to find the length of a tangent?

    Pythagoras in the triangle with the radius.

  12. A radius is 5 cm and the distance from the centre to the point is 13 cm. How long is the tangent?

    12 cm.

  13. Which side is the hypotenuse in a tangent triangle?

    The line from the centre to the outside point.

  14. A chord is 16 cm long and the radius is 10 cm. How far is the chord from the centre?

    6 cm.

  15. What should you draw first in a tangent question?

    The radius to the point of contact.

  16. Can a line touch a circle at two points and be a tangent?

    No, a tangent touches at exactly one point.