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Question
Using a graph paper, plot the points A (6,4) and B (0,4).
(i) Reflect A and B in the origin to get the images A’ and B’.
(ii) Write the co-ordinates of A’ and B’.
(iii) State the geometrical name for. the figure ABA’B’.
(iv) Find its perimeter.
Solution
(i) 
(ii) A' (-6, -4) and B' (0, -4)
(iii) ABA'B' is a parallelogram.
(iv) From the figure AB = 6, BB' = 8, A'B' = 6
In ΔABB', (AB)2
= (AB)2 + (BB')2
= 62 + 82
= 100
∴ AB' = 10 = A'B' ...{ABA'B' is a parallelogram}
∴ Perimeter of ABA'B'
= AB + BA' + A'B' + B'A
= 6 + 10 + 6 + 10
= 32 units.
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