Question

which triangle has congruent angles?
select one:
a. equilateral
b. obtuse
c. right
d. isosceles

an angle formed by extending a side of a triangle is called a/n
select one:
a. complementary angle
b. remote interior angle
c. vertical angle
d. exterior angle

Explanation:

For the first question: Congruent angles mean all angles are equal. An equilateral triangle has all three interior angles equal to $60^\circ$. Obtuse triangles have one angle greater than $90^\circ$, right triangles have one $90^\circ$ angle, and isosceles triangles only have two congruent angles, so only equilateral triangles have all congruent angles.
For the second question: By definition, an exterior angle of a triangle is formed when one side of the triangle is extended outward. Complementary angles sum to $90^\circ$, remote interior angles are the non-adjacent interior angles to an exterior angle, and vertical angles are opposite each other at an intersection, so none of these match the description except exterior angle.

Answer:

1. a. equilateral
2. d. exterior angle