Question

In the diagram, the shaded triangle is reflected in the line $x=4$
The image of the point $M$ under the above reflection is:

• A. $(3,2)$
• B. $(4,3)$
• C. $(7,3)$
• D. $(7,1)$

Answer 1

Answer: (C)

$(7,3)$

Given a point $M(X,Y)=(1,3)$.

Let $M^{\prime }(x^{\prime },y^{\prime })$ be its image in line $x=4$.

For reflection in line $x=4$,

$y^{\prime }=y$ and $x^{\prime }=4+(4-x)=4+4-1=7$.

So, $M^{\prime }$ is $(7,3)$.