Question

4.If the point D(4, 6), E(10, 2k) and F(12, 14) are collinear, then find the value of k.

Answer 1

Answer:

k =-3.74

Step-by-step explanation:

colinear means all 3 points present in a line ,so we can use triangle area formula (which you study in coordinate geometry =1/2(x1(y2-y3)+x2(y3-y 1)+x3(y1 -y2))=0, here x1=4,x2=10,x3=12,y1=6,y2=2k,y3=14, we get 1/2(4(2k-14)+10(14-6)+12(6-3k)=0, 1/2(8k+56+80+72+48k), =1/2(56k+208)=0, 56k=-208, k=-208/56 k=- 3.74