Question

If the base of isosceles triangle is 55° then that is sum of the vertical angle

Answer 1

The base of the isoceles triangles is 55°

So:

the base angles are equal

Hence they are 55° each

The sum of base angles is 55°+55°

==> 110°

Then the opposite angle+110°=180°

[By angle sum property]

==> angle=180°-110°

==>70°

The vertical angle is 70°

Hope it helps you.