A triangle has corners at (0,5), ( 1, -6),and(8, -4 )#. If the triangle is reflected across the x-axis, what will its new centroid be?

1 Answer
May 18, 2016

(3,53)

Explanation:

The centroid C also known as barycenter, of a triangle with vertex given as {a,b,c} is calculated as:
C=a+b+c3. Our triangle has a=(0,5),b=(1,6),c=(8,4) so
we have C=(3,53). Reflecting the triangle across the x axis
implies in reflecting also the barycenter. Choosing the x axis facilitate calculations because the C point perpendicular projection over the x axis is exactly its x component with y=0. Call this projected point Cx=(3,0). The reflected point is calculated as Cr=C+2(CxC)=(3,53)