Question

Find the value of k, Points (1,3) , (3,9) and (0.k) are collinear.

• A. 3
• B. -3
• C. 1
• D. 0

Answer 1

Answer:

D. 0

If the points are collinear then they will not form a triangl.

The points are (1,3),(3,9),(0,k)

$Area=\frac{1}{2}[x_1(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)]=0$

We have,

$x_1=1,y_1=3,x_2=3,y_2=9,x_3=0,y_3=k$

Putting these values

$\frac{1}{2}[1(9-k)+3(k-3)+0(3-9)]=0$

$1(9-k)+3(k-3)+0=0$

$9-k+3k-9=0$

$2k+0=0$

$k=0$