Question

Find the centroid of the triangle formed by a line x=0,y=0and x+y=9

Answer 1

when x=0 y=9 & when y=0 x=9
so the coordinates of the three vertices of the triangle are (0,0);(0,9);(9,0)
the formula for centroid of a triangle is (x1+x2+x3)/3 & (y1+y2+y3)/3

so the coordinates of the centroid are (3,3).

Answer 2

first of all find vertices of traingle form by these lines ,

e.g ( 0 , 0) , (0, 9) and (9, 0)

we know,
centroid is the point of intersection of median of triangle .
if (x1 , y1) (x2, y2) and (x3 , y3) are three vertices of ∆
then, centroid ={ (x1 +x2+x3)/3 , (y1+y2+y3)/3 }

now,

centriod of ∆ ={ (0 +9 +0)/3 , (0 +0+9)/3}
=(3, 3)