Sketch the figure: two different isosceles triangles with perimeter 4a + b

The two triangles with the given perimeter is attached .

Perimeter is the sum of all sides.

For the first triangle , sies are  2a,2a and b.

So the perimeter is

For the second triangle, sides are a,a, and 2a+b. Therefore perimeter is

So for both triangles, perimeter is