ত্রিভুজের ক্ষেত্রফল

Find the value of mm if the points (5,1),(2,3)(5, 1), (2, 3) and (8,2m)(8, 2m ) are collinear.

হানি নাটস

If three points are collinear, then the area of the triangle formed by taking these points as vertices should zero.
Area =12=\dfrac{1}{2}[5(32m)+2(2m1)+8(13)]{5(3-2m)+2(2m-1)+8(1-3)}]......(using determinant formula of area of triangle)

=12= \dfrac{1}{2}[1510m+4m2+(16)]{15-10m +4m-2+(-16)}]
=12= \dfrac{1}{2} {15186m15-18-6m}
=12 = \dfrac{1}{2}(36m)=0(-3-6m)=0
(3+6m)=0\Rightarrow (3+6m)=0
m=12m=-\dfrac{1}{2}.

ত্রিভুজের ক্ষেত্রফল টপিকের ওপরে পরীক্ষা দাও