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Question
Find the co-ordinates of the images of the following under reflection in the origin:
(3, -7)
Solution
The reflection (image) of the point P(3, -7) at the origin is the point P'(-3, 7).
Note: To find the reflection of a point in the origin change: (a) The sign of abscissa; i.e., X co-ordinate. (b) The sign of ordinate; i.e., Y co-ordinate.
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RELATED QUESTIONS
State the co-ordinates of the following point under reflection in origin:
(–2, –4)
State the co-ordinates of the following point under reflection in the line y = 0:
(–3, 0)
Find the image of point (4, -6) under the following operations:
(i) Mx . My (ii) My . Mx
(iii) MO . Mx (iv) Mx . MO
(v) MO . My (vi) My . MO
Write down a single transformation equivalent to each operation given above. State whether:
(a) MO . Mx = Mx . MO
(b) My . MO = MO . My
The point (–5, 0) on reflection in a line is mapped as (5, 0) and the point (–2, –6) on reflection in the same line is mapped as (2, –6).
- Name the line of reflection.
- Write down the co-ordinates of the image of (5, –8) in the line obtained in (a).
State the co-ordinates of the images of the following point under reflection in the origin:
(9,-9)
Find the co-ordinates of the images of the following under reflection in the origin:
`((-5)/(2),(-1)/(2))`
Find the co-ordinates of the images of the following under reflection in the origin:
(0, 0).
Point A (2, -4) is reflected in origin as A’. Point B (- 3, 2) is reflected on X-axis as B’.
(i) Write the co-ordinates of A’.
(ii) Write the co-ordinates of B’.
(iii) Calculate the distance A’B’.
Give your answer correct to 1 decimal place, (do not consult tables).
The image of triangle OXY under reflection in the origin, O is the triangle OX1Y1, where X1(-3, -4) is the image of X and Y1, (0, -5) is the image of Y.
(i) Draw a diagram to represent this information and write down the co-ordinates of X and Y.
(ii) What kind of figure is the quadrilateral XYX1Y1? Give reason for your answer. State, with a reason, whether the figure XYX1Y1 has any lines of symmetry.
(iii) Find the co-ordinates of X2, the image of X under reflection in the origin followed by reflection on the Y-axis.
(iv) Find the co-ordinates of Y2, the image of Y under reflection on the X-axis followed by reflection in the origin.
Use a graph paper for this question (take 10 small divisions = 1 unit on both axis).
Plot the points P (3, 2) and Q (-3, -2), from P and Q draw perpendicular PM and QN on the X- axis.
(i) Name the image of P on reflection at the origin.
(ii) Assign, the. special name to the geometrical figure. PMQN and find its area.
(iii) Write the co-ordinates of the point to which M is mapped on reflection in (i) X- axis,
(ii) Y-axis, (iii) origin.
