Question 1006809

Show that P(1,2), Q(-11,2) and R(-5,6) are vertices of an isosceles triangle.
Find the Lengths of all three sides
PQ=
QR=
PR=

Please help I have no Idea where to start...
<pre>Since P & Q have the same y-coordinate, PQ is a HORIZONTAL LINE that's parallel to the x-axis. Its distance is therefore 1 - - 11, or 12. 
Now just use the distance (d) formula: {{{d = sqrt((x[1] - x[2])^2 + (y[1] - y[2])^2)}}} to find the distances from P(1, 2) to R(- 5, 6) and from Q(- 11, 2) to R(- 5, 6).
These 3 distances should reveal whether &#916;PQR is isosceles or not.