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# Unsure how to get to the answer (Reflections) watch

1. Howdy .

I am stuck on part b on the below question.

The answer says it is the line y = x

How do I find this out for myself as I can't see how it is y = x. What method could I use so I can answer these types of questions?

I can do all the easy questions but find it difficult with this style of question.

2. (Original post by makin)
Howdy .

I am stuck on part b on the below question.

The answer says it is the line y = x

How do I find this out for myself as I can't see how it is y = x. What method could I use so I can answer these types of questions?

I can do all the easy questions but find it difficult with this style of question.
Write down the coordinates of every vertex of the shape A. Then write down the coordinates of every vertex of shape C. You should notice that there is a relation between, say, (5,2) and (2,5) such that the numbers are swapped, ie x's and y's are swapped ie there has been a reflection in the line y=x.

Though at this level you should just see it by inspection really... draw the line y=x then rotate everything such that this line seems vertical for you, then maybe the reflection will be more obvious.

EDIT: Also shape A seems to be the red shaded bit, not the trapezium with the point (4,3) as a vertex, if that's what you've been thinking.
3. (Original post by makin)
Howdy .

I am stuck on part b on the below question.

The answer says it is the line y = x

How do I find this out for myself as I can't see how it is y = x. What method could I use so I can answer these types of questions?

I can do all the easy questions but find it difficult with this style of question.

If a shape A is reflected in a line L into shape B, then corresponding points on And B are the same distance from L.

So choose a point on A which you know is reflected to a point on B, and draw the straight line between them. Bisect that line at point M1.

Choose another pair of points on A and B, and repeat the above to get M2. Now M1 and M2 must lie on the line of reflection, so draw the line through them.

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Updated: October 23, 2017
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