A triangle has corners at (6, 3 )(6,3), ( 8, -2), and ,and(1, -1 )#. If the triangle is reflected across the x-axis, what will its new centroid be?

1 Answer
May 5, 2016

(5 ,0)

Explanation:

The first step here is to find the coordinates of the centroid of the triangle.

Given the 3 vertices of a triangle (x_1,y_1),(x_2,y_2),(x_3,y_3)(x1,y1),(x2,y2),(x3,y3)

Then the centroid is calculated as follows:

color(red)(|bar(ul(color(white)(a/a)color(black)(x_c=1/3(x_1+x_2+x_3), y_c=1/3(y_1+y_2+y_3))color(white)(a/a)|)))

let (x_1,y_1)=(6,3),(x_2,y_2)=(8,-2),(x_3,y_3)=(1,-1)

rArrx_c=1/3(6+8+1)" and " y_c=1/3(3-2-1)

coordinates of centroid = (5 ,0)

Under a reflection in the x-axis

A point (x ,y) → (x ,-y)

Since the point (5 ,0) is on the x-axis, it's position will remain the same under a reflection in the x-axis.

hence (5 ,0) → (5 ,0)