The vertices of a triangle are P(–4, 1), Q(–2, –8), and R(8, –1). Name the vertices of the image reflected across the y-axis.
1.P'(–4, –1), Q'(–2, 8), R' (8, 1)
2.P'(4, –1), Q'(2, 8), R'(–8, 1)
3.P'(4, 1), Q'(2, 8), R'(–8, –1)
4.P'(–4, 1), Q'(–2, –8), R'(8, –1)
please help
To reflect a point across the y-axis, you need to change the sign of its x-coordinate while keeping the y-coordinate the same.
Let's apply this rule to each vertex of the triangle:
- Vertex P(–4, 1) would become P'(-(-4), 1) = P'(4, 1)
- Vertex Q(–2, –8) would become Q'(-(-2), -8) = Q'(2, -8)
- Vertex R(8, –1) would become R'(-8, -1)
Therefore, the vertices of the reflected triangle across the y-axis are P'(4, 1), Q'(2, -8), and R'(-8, -1).
So the correct answer is option 2: P'(4, –1), Q'(2, 8), R'(-8, 1).
reflection across the y-axis takes
(x,y) -> (-x,y)
so, just flip the signs of all the x-values.