Given:
The figure of a triangle.
To find:
The category of the triangle.
Solution:
In the given triangle two angles are equal and their measure is 78 degrees. So, the measure of third angle is
(Angle sum property)
In the given triangle only two angles are equal in means their opposite sides are also equal.
We know that base angles of an isosceles triangle are equal. So, the triangle is isosceles.
All angles are less than 90 degree. So, the triangle is acute.
Therefore, the given triangle is an isosceles acute triangle and the correct option is B.