construction of tangent
Let be the centre of the given circle and the given point. With as diameter, draw the circle (see midpoint). If and are the points where this circle intersects the given circle, then by Thales’ theorem, the angles and are right angles. According to the definition of the tangent of circle, the lines and are required tangents.
The line segment is
The convex angle is called a tangent angle (or tangent-tangent angle) of the given circle and the convex angle the corresponding central angle. It is apparent that a tangent angle and the corresponding central angle are supplementary. The chord is the tangent chord corresponding the tangent angle and the point (see equation of tangent chord (http://planetmath.org/EquationOfTangentOfCircle)!).
The tangent angle is the angle of view of the line segment from the point .
|Title||construction of tangent|
|Date of creation||2013-03-22 17:36:04|
|Last modified on||2013-03-22 17:36:04|
|Last modified by||pahio (2872)|