Question

What is the distance between point (5, 9) and its reflection across the y-axis?

Answer 1

Answer:

10 units

Step-by-step explanation:

Given: Point is $(5,9)$

To find: the distance between point $(5,9)$ and its reflection across the y-axis

Solution:

Reflection of point $(x,y)$ is $(-x,y)$ across the y-axis

So, reflection of point $(5,9)$ is $(-5,9)$ across the y-axis

Distance between points $(x_1,y_1),(x_2,y_2)$ is given by $\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

Let $(x_1,y_1)=(5,9),(x_2,y_2)=(-5,9)$

So,

the distance between point (5, 9) and its reflection across the y-axis = $\sqrt{(-5-5)^2+(9-9)^2}=\sqrt{100}=10$

Distance = 10 units