Posted by Ted on .
show that triangle PQR with P(2,10, Q(1,5) and R(5,2) is isosceles.

math 
MathMate,
Find out the lengths of each side using the distance formula:
D=√((x2x1)²+(y2y1)²)
If two sides are identical in length, the triangle is isosceles.
If all three have the same length, then it is equilateral.