Centroid of a right angle triangle

[D0m]

Hi i have a right angle tringle, base=1200m and h=400.

I have trouble understanding on how to determine the centroid i know one side will be 2/3*x and another side would be 1/3*y. But i don't understand how to write it out.

A friend said its 1/3*1200*400*2/3*1200, but i have no idea and think its wrong.

My attempt: 1. 1/3*400*2/3*1200 or
2. (0.5*400*1200)*(2/3*1200)

please help on how to find the centroid

 

[Xisune]

Centroid of a triangle:

(x1 + x2 + x3)/3 , (y1 + y2 + y3)/3