Let A(4,2) ; B(6,7) ;C(1,4) be the vertices of triangle ABC,to find

[i]The median from A meets BC at D,To Find co-ordinates of D

[ii]Find the co-ordinates of the point P on AD such that AP:PD = 2:1

[iii]Find the co-ordinates of point Q and R on medians BE and CFrespectively such that BQ:QE = 2:1

[iv] what do you observe ?

pls help ....


As AD is the median of the triangle so D is the midpoint of BC 
Co-ordinates of D using midpoint formula is  D=(6+12),(7+42)=72,112Now it is given AP:PD = 2:1 A(4,2)..........P(x,y).........D72,112Hence coordinates of P using section formula is P=2×72+1×42+1,2×112+1×22+1Coordinates of P is (113,133)Now BE is also a median so E is the midpoint of AC Co-ordinates of E using midpoint formula is  E=(4+12),(2+42)=52,3Now it is given BQ:QE = 2:1 B(6,7)..........Q(x,y).........E52,3Hence coordinates of Q using section formula is Q=2×52+1×62+1,2×3+1×72+1Coordinates of Q is (113,133)Now CF is also a median so F is the midpoint of AB Co-ordinates of F using midpoint formula is  F=(4+62),(2+72)=5,92Now it is given CR:RF = 2:1 C(1,4)..........R(x,y).........F5,92Hence coordinates of R using section formula is R=2×5+1×12+1,2×92+1×42+1Coordinates of R is (113,133)

It is observed that points P,Q and R are having the same co-ordinates.Hence that point is the centroid where medians of a triangle meet.Hence we can say that centroid divides the median in the ratio 2:1

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