Explanation:
P(-1,1), Q(2,3), R(2,1)
Let P(-1,1)be x1and y1
Q(2,3)be x2 and y2
therefore, by distance formula
d(PQ)= root (x2-x1)^2+(y2-y1)^2
= root[ 2-(-1)] + (3-1)
=root (2+1)^2+2^2
= root (3square +2square )
= root 9+4
d( PQ) = root 13.........(1)
Now find distance QR and PR then prove that the three sides are not equal and therefore it is a scalene triangle
2nd also do the same.