Special Triangles

Problem : Decide whether or not the triangle below is isosceles.

Problem : Decide whether or not the triangle below is isosceles.

Problem : Decide whether or not the triangle below is isosceles.

Problem : If the perimeter of a triangle is 15, and two of the side lengths are 3 and 8, can the triangle be isosceles?

Problem : Given: Triangle ABC is isosceles; angle A is 110 degrees; the length of side BC is 6; the length of side CA is 4. What is the perimeter of triangle ABC?