J20
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Reflections<br />
Under a reflection:<br />
(a)<br />
(b)<br />
(c)<br />
(d)<br />
a point and its image are equidistant from the mirror line.<br />
the mirror line is a perpendicular bisector of the line joining a point and its image.<br />
points on the mirror line are invariant.<br />
an object and its image are indirectly congruent.<br />
In the Cartesian plane, a reflection is described by stating the equation of the mirror line.<br />
Example<br />
Triangle PQR is such that P(-2, 1), Q(-3, 3) and R(2, 2) are the vertices. Find the<br />
coordinates of its image under a reflection in the line x = 2.<br />
Solution<br />
When the triangle is reflected on the line x = 2, the coordinates of the image are<br />
P 1(6, 1), Q 1(7, 5) and R 1(2, 2).<br />
R lies on the mirror line and is invariant
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