A triangle has corners at (3, 8 ), ( 5, -2), and ( 1, -1)#. If the triangle is reflected across the x-axis, what will its new centroid be?

1 Answer
May 14, 2016

Coordinates of centroid will be (3,-5/3)

Explanation:

The centroid of a triangle whose vertices are (x_1,y_1), (x_2,y_2) and (x_3,y_3) is given by

((x_1+x_2+x_3)/3,(y_1+y_2+y_3)/3)

Hence centrid of given triangle is ((3+5+1)/3,(8+(-2)+(-1))/3) or (3,5/3).

Now, when a point (x,y) is reflected across the x-axis, its coordinates become (x,-y) and hence

New coordinates are (3,-8), (5,2) and (1,1) and even
coordinates of centroid will have same rule.

Coordinates of centroid will be (3,-5/3)