Question 1006809
Use the distance formula to calculate the distance between each pair of points. 


Example: the distance between P and Q is equal to the length of side PQ.


The distance formula is {{{d = sqrt((x[1]-x[2])^2+(y[1]-y[2])^2)}}}


You can use this solver

<a href = "http://www.algebra.com/algebra/homework/Length-and-distance/distance-formula.solver">http://www.algebra.com/algebra/homework/Length-and-distance/distance-formula.solver</a>

to calculate the three distances to get the side lengths



Using the solver, the segment lengths are


{{{PQ=12}}}
{{{QR=2*sqrt(13)}}}
{{{PR=2*sqrt(13)}}}


So we see that {{{QR = PR}}}. We have exactly 2 equal sides. So this triangle is definitely an isosceles triangle.