Question

3 consecutive vertices of a parallelogram areA(1,2) B(2,3) C (8,5).find the 4th vertex​

Answer 1

Answer:

D(7,4)

Step-by-step explanation:

W.K.T., in a parallelogram the diagonals bisect each other at right angles

So, using mid-point formula we can find the required answer (there is an alternate long method also),

mid-point of AC = mid-point of BD

[1+8/2,2+5/2] = [2+x/2,3+y/2]

[9/2,7/2] = [2+x/2,3+y/2]

[9,7] = [2+x,3+y]

9=2+x   &  7=3+y

x=7,y=4

Therefore the coordinates of fourth vertex is D(7,4).