+1776 All the sides of a triangle have integer length. The perimeter of the triangle is 5 and the triangle is isosceles. How many such non-congruent triangles are there?
+410 Set the side lengths of the triangle to be x,x,y
2x+y=5, so 2x<5 and x≤2.
Therefore, because x is a positive integer, x is either 1 or 2.
But we need to be careful because 1, 1, 3 is not a triangle.
So the only possibility is 2, 2, 1.
