How many edges are there? A. 15 B. 9 C. 16 D. 12
2 answers:
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<em>Options:</em>
<em>Rotation of 180° about point B </em>
<em>Rotation of 90° about point b </em>
<em>Reflection over the x-axis </em>
<em>Translation down 2 units</em>
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Answer:
Rotation of 180° about point B
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Step-by-step explanation:
Considering coordinates of point B
Assume the coordinates of the line at point B is (x,y)
i.e.
First, we need to determine the slope at point B
Taking coordinates about the origin.
The slope of B is:
Where
--- origin
becomes
Taking the options one after the other:
Option A.
When rotated by 180°, the resulting coordinates of B would be
Taking the slope of B'
The slope of B is:
Where
--- origin
becomes
Notice that the slope of B and B' is the same;
<em>Hence:</em>
<em>Rotation of 180° about point B answers the question</em>
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<em>There's no need to check for other options</em>