Answer:
if the exterior angle of the base is 100 them the measure of the angle at each base is 20 and the measure of the angle of vertex is 100
Step-by-step explanation:
Given the isosceles triangle has an exterior angle of a base as 100
Let, triangle ABC be an isosceles triangle.
BC is base and C is vertex
Where Angle B = Angle A
We know that the exterior angle of the triangle is the sum of corresponding interior angles
Hence,
Angle A + Angle C = 100.
From property of triangle,
Angle A + Angle B + Angle C =180
100 + Angle B =180
Angle B =180-100=80 is angle at base
Now,
Angle B = Angle A = 80
Angle A + Angle C = 100.
80 + Angle C = 100.
Angle C =20 is angle as Vertex.
